Chem Units 1-3 Final

unit 1 Measuring Matter & Energy

vocab

calorie - energy required to raise the temp of one gram of water by one degree Celsius

Mass- measure of the amount of matter in an object

Weight - force exerted on an object by Earth’s gravitational pull

derived units - combining SI units into compound units

Density - ratio of mass & volume

potential energy - stored energy associated with position, shape or condition of an object

Kinetic energy - energy associated with the motion of an object

energy transfer - passing from one object to another

temperature - average kinetic energy of the particles that make up a sample of matter

conversion factors - ratios relating the value of one unit measure to another

accuracy - closeness of a measurement to the correct or accepted value of the quantity measured

precision - closeness of measurements of the same quantity made in the same way

significant figures - measurement consist of all the digits known with certainty + the first estimated digit

captive zeros - zeros appearing between nonzero digits

leading zeros - zeros that precede nonzero digits

trailing zeros - zeros at the end of a number

• matter - anything that takes up space and has mass

  • physical property - property that can be measured/observed without changing the identity of matter

    • Density 

    • Solubility 

    • Conductivity 

    • Magnetic attraction 

    • State of matter (gas, liquid, solid)

    • Melting and boiling points 

    • Viscosity (aka thickness)chemical properties - only observed after the identity of a substance changes

  • extensive property - property that depends directly on the amount of a substance present

  • intensive property - property that does not depend on the amount of a substance present

So matter…it has different states: the classic gas solid and liquid what are the diffs?

MEMORY TIP:

✲ The faster the particles move the easier it is to walk through the substance. So you cannot walk through a solid because the particles can only vibrate. You can walk through water because the particles are quicker, however it's still a challenge, but with gas since the particles are exponentially faster than particles of a solid you can walk through them with ease. 

• types of extensive properties

  • mass, volume (changes based on size/ amount)

• types of intensive properties

  • density, melting point, boiling point, and conductivity (does not depend on amount)

    pure substance - fixed composition

mixture - blend of two or more kinds of matter

homogeneous mixtures/solutions - uniform mixtures

heterogeneous mixtures - mixtures that are not uniform throughout

• filtration - separate a solid with larger particles from a liquid with smaller particles

• Centrifugation - separate certain solid components. The centrifuge spins rapidly, causing the solids to settle at the bottom of the test tube.

• paper chromatography - used to separate dyes or pigments. The different substances move at different rates on the paper.

pure substances

pure substances are ALWAYS homogeneous

compounds - substances with constant composition that can be broken down into elements by chemical processes

elements - cannot be decomposed by chemical or physical means

systems

model - pattern, plan, rep or description designed to study the behavior of matter

system - set of interacting, interrelated or interdependent components that form a complex whole

• open system - energy and matter flow in and out freely

• closed system - little to no exchange of matter but energy may be exchanged

• isolation system - neither matter or energy can flows in or out

Engineering process

• criteria - goals for the solution

• constraint - limitations of the design

• delimiting

• the process of defining the constraints of the solutionTechniques to separate mixtures

  tradeoff - exchange for one thing in return for another

• multiscale modeling - rep a system using various scales

practice Q’s

Which of the following are chemical changes?

• wooden logs burning to form ash

• hydrogen and oxygen forming from water

An example of a pure substance is

• carbon dioxide

A mixture is homogeneous if it has a uniform composition. A mixture is

heterogeneous if its composition is not uniform. A mixture can often be separated by techniques such as evaporation or filtration.

A group of chemical engineers are developing a medication to treat a disease. Which statement describes a possible constraint for the medication?

• The cost of producing the medication will be kept as low as possible.

The density of a liquid substance in a container is an intensive physical property of the substance, so it can be used to help identify it. The volume of the substance is an extensive property, so it cannot be used in identification because it changes with the amount of the substance present.

An engineer is developing a process to separate a pure substance from a chemical reaction mixture. Which of the following would be considered a constraint on the engineering design process for the separation technique?

• The budget for the process is $100 000

A student determines the density of a substance as 1.536 g/mL. The accepted value of the density is 1.446 g/mL. What is the percentage error in the student's value?

• The percentage error is 6.224 %.

A hot metal block is placed into a beaker of cold water. Explain what happens to the thermal energy of the system.

What is scientific notation, and why it is useful for reporting scientific measurements?

A block of ice is placed outside on a hot summer day. Describe the changes in particle motion and the corresponding changes in energy as the ice melts and eventually becomes water vapor.

what is chemistry? - study of the composition of matter, the physical and chemical changes that matter undergoes, and the energy absorbed or released during those changes.

conversions

• 1g=1000mg

• 1cm=10mm

• 1L=1000mL

Smallest to largest:

• nanogram, microgram, milligram, centigram, kilogram, megagram

• percentage error

  • value experimental-value accepted/value accepted x 10

• how to know which percent error is most accurate

  • smallest = more accurate

• Volume

  • L x W x H

• Accuracy

  • closeness to the true value

• Precision

  • closeness to other answers trying to find the true value

• Density

  • amount of mass per volume an object contains

• Magnetic attraction

  • the ability of a substance to be attracted to a magnet

• Solubility

  • the amount of a substance that can dissolve in a given amount of another substance

• State of matter

  • solid, liquid, gas, plasma, Bose-Einstein condensate

• Physical change (salt dissolving in water)

  • Change occurs without a change in the substance's chemical composition at a molecular state

• plasma (most of universe)

• gas in which the particles have so much energy that they broke apart and became electrically charged

• Chemical properties of sodium in water

  • faster than sodium, more smoke, flame

• Chemical properties of potassium in water

  • reacts so fast it can be explosive

Chemical properties are only observed

• when one attempts to change the identity of the substance

• Chemical change

  • particles of a substance are rearranged, resulting in a change in chemical composition

• Reactants

  • substance undergoing the change

• Products

• the new substance found produced by chemical reaction

vocab

HEAT

• Thermodynamics - relationship between heat and other forms of energy, how it can be transferred and transformed

• Temperature - avg. KE of particles in a substance; property of all states of matter

• Thermal equilibrium - when two systems with different temperatures reach the same temperature, resulting in no transfer of energy

• zeroeth law - if two bodies are in thermal equilibrium with a third body, they are in thermal equilibrium

• heat transfer - thermal energy is transferred

• law of conservation of energy - energy cannot be created or destroyed

• heat capacity - The ratio of the energy needed to change the temperature of a system compared to its change in temperature; depends on mass & type of material; extensive property

• specific heat capacity - intensive property; the amount of energy required to raise the temperature of one gram of a substance by one kelvin; (cal/g•°C)

  • The high specific heat capacity of liquid water makes it useful for absorbing excess energy in industrial processes

MASS

• molar mass - mass of one mole of a substance

  • 22.4L

  • 6.022×10²³ particles

• avogadros law - equal particle numbers result from equal pressure, temperature, and volume

PHASE CHANGES

• phase change - transition between different states of matter (melting, vaporization, condensation)

• vaporization - change from liquid—>gas

  • evaporation

    • particles at the surface of a liquid gain enough energy to become a gas

  • condensation

    • gas—>liquid

• sublimation - solid—> gas (skips liquid state)

• deposition - gas—>solid (skips liquid stage)

• triple point - all 3 states coexist

• open system - energy and matter flow in and out freely

• closed system - little to no exchange of matter but energy may be exchanged

• isolation system - neither matter or energy can flows in or out

BEHAVIOR OF GASES

• internal energy - state of a substance

  • ex: temperature

• volume - amount of physical space occupied by a gas

• pressure - force exerted by gas particles colliding on surfaces

• barometers - instruments used to measure air pressure

• (STP) - standard temperature and pressure - standard conditions for measuring molar volume of a gas

• ideal gas - hypothetical gas used to describe behavior of real gases

• (KMT) - Kinetic molecular theory

  • describes properties of ideal gases

  • constant motion/negligible forces between particles

  • elastic collisions - no net loss in KE

    • momentum and KE are conserved

• pressure vs volume (inverse) —> volume (up) = pressure (down)

  • temperature is constant

• volume vs temperature (direct) —> volume (up) = temperature (up)

ENERGY TRANSFER

• conduction - transfer of thermal energy by the collision of particles when objects or substances are in contact

  conduction misc. bigger temp diff. conduction happens at higher rate + materials w/ low conductivity make good insulators

• convection - cycling of air due to the differences in densities; occurs in gases & liquids

  • if convection natural = natural convection

  • if convection not natural = forced convection

• Thermal radiaton - thermal energy is transferred through waves such as visible light, infrared radiation, and other types of electromagnetic waves. CAN FEEL COOLER B/C OF THERMAL RADIATION NOT JUST HOTTER

• diffusion - Gases spread out spontaneously and mix with other gases in a process

• entropy - show how disordered a system is (most to least disordered gas, liquid, solid)

• increase entropy = increase energy

• Second law of thermodynamics - all real processes increase the entropy of the universe

• smaller system can be made more ordered by using energy from the outside, creating greater entropy in the larger system

• energy flows from the higher temperature system to the lower temperature system aka energy flows from higher energy to lower energy objects or particles

• computational model - computer performs this analysis or provides a way to model the behavior of matter

• Work - transfer of energy to a system by the application of force that causes the system to move in the direction of the force

• energy is defined by ability/capacity to do work

• Heat engine - energy is transferred to the system in the form of heat. system transforms that energy to do work on its surroundings

  • The amount of work that a heat engine can do on its surroundings cannot be more than the amount of energy transferred to the heat engine.

  • gas does work on its surroundings when its temperature increases

  • engine - device that transforms energy into mechanical force or motion

• Geothermal energy - Energy from underground sources

  • dry steam plant - uses steam from an underground geothermal source to turn a turbine

  • binary cycle power plant - transfers energy from geothermal water to another liquid

  • perpetual motion machine - hypothetical machine that can perform work without any input of energy

  • spontaneous - not requiring an outside source of energy to proceedpractice Q’s

EARTH AND SPACE STUFF

• tectonic plates

  pieces of Earth’s very thin and rigid outer shell

types of chemistry

• Physical

  • the study of the properties and changes of matter and their relation to energy

• Analytical

  • the study of the composition of substances

• theoretical

  • the studies of chemical structure and its dynamics

• inorganic

  • the study of non organic substances

• organic

  • the study of most carbon based compounds

• biochemistry

  • the study of the chemistry of living things

unit 2 Heat & Energy in the Earth System

vocab

• Thermodynamics

  • the relationship between heat and other forms of energy and the ways energy can be transferred and transformed (flow of energy in a system)

• Internal energy

  • The total kinetic and potential energy of all particles in a system (ex: thermal)

• Changing mass or speed

  • effects kinetic energy

• Changing mass, charge, or moving system in field

• effects potential energy

• Adding or removing energy

  • effects internal energy

• Volume

  • amount of physical space occupied by gas (cm^3)

• Pressure

  • the amount of force exerted per unit area of a surface (Pa or N/m^2 or psi)

• barometer

• Used to measure atmospheric pressure

• Temperature

  • average kinetic energy of the particles of a substance

• Thermal equilibrium

  • when two systems have the same temperature so no energy transfer occurs

• Zeroth law of thermodynamics

  • If two thermodynamic systems are in thermal equilibrium with a third, then they are in thermal equilibrium with each other

• Avogadro's number

  • 6.022 x 10^23 The number of gas particles in exactly one mole of a substance

• STP

  • standard temperature and pressure (by convection gases are analyzed at 1 atm of pressure and 273.15K)

• As pressure decreases

  • volume increases (inverted relationship)

• as temperature increases

  • pressure increases (directly related)

• as temperature increases

  • volume increases (directly related)

• Why does condensation form?

  • The stuff inside the system takes energy from the outside of the system (bottle ex)

• Avogadro's law

  • the equal volumes of gases at the same temperature and pressure have equal numbers of particles

• 1 mol of any gas at STP

• 22.4 L

• Molar mass

  • the mass of one mole of a substance

• KE = 1/2mv^2 (kinetic energy of a gas depends on mass and speed)

• As gas density increases

  • speed and movement of the particles decreases

• kinetic molecular theory

  • explains the properties of an ideal gas, constantly moving particles, mostly empty space with limited contact, do not exert much force on each other, no loss of kinetic energy after collision, gas temp is directly proportional to KE

• Ideal gas

  • hypothetical gas in which the particles ave no volume and no attractions for each other (low temp high pressure, gases attract less in low temperatures due to slower speeds)

• vaporization

  • boiling or evaporation turning liquid to gas

• sublimination

  • when a solid turns directly to gas (dry ice)

• deposition

  • gas directly to solid (frost)

• triple point

  • the pressure and temperature conditions where all three states may exist

• In lower pressures

  • less energy must be added or removed to change somethings state

• Thermal pollution

  • temperature increase in a body of water caused by human activity (heat dissolves oxygen)

• Thermal energy

  • total kinetic energy of the particles in a substance (depends on amount and temp)

• Law of conservation of energy/ 1st law thermodynamics

  • Energy can not be created or destroyed

• When two or more objects are in thermal equilibrium

  • energy is no longer transferred between them (energy between both objects is equal)

• heat capacity

  • the ratio of energy needed to change the temp of a system compared to its change in temp (extensive, depends on amount of energy)

• Heat capacity of a system depends on

  • mass and material

• Specific heat capacity

  • intensive property of a substance that represents the quantity of heat required to raise the temperature of 1 gram of the substance by 1K

• High heat capacity

  • absorbs and releases large amounts of heat before changing temperature

• Specific heat capacity can vary with

  • pressure (cp is for heat capacity with standard pressure)

• Calorimeter

  • calculates the specific heat capacity of a substance

• conduction

  • Form of heat transfer where heat energy is directly transferred between molecules through direct contact

• Thermal conductivity

  • The rate at which a system transfers energy via conduction (depends on type of material and temp difference between object and heat source, greater temp difference = higher rate)

• Low thermal conductivities

  • air (things with low thermal conductivity makes good insulators) (solids are best conductors, liquids, then gas)

• Convection

  • when a space is heated, the warmer gas with more kinetic energy rises, making the air less dense, and the cooler denser air will sink, pushing the warm air upward (occurs in liquid and gas)

• natural convection

  • when convection is driven by natural forces like a difference in densities

• forces convection

  • when something like a fan causes the liquid or gas to move

• Thermal radiation

  • a mode of energy transfer that occurs when thermal energy is transferred through waves such as visible light, infrared radiation, and other types of electromagnetic waves (does not require medium like the other two)

• diffusion

  • when gases spread out spontaneously and mix with other gases to eventually fill up a space (bromine in container of air)

• Entropy

  • how disordered a system is

• States from highest to lowest entropy

  • Gas, liquid, solid (low organization of particles to high)

• Entropy is directly related to

  • energy

• second law of thermodynamics

  • All natural processes increase entropy, meaning that energy will always be lost to surroundings.

• third law of thermodynamics

  • As the temperature of a system approaches absolute zero, and entropy reaches its lowest possible value.

• zeroth law

  • If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

• work

  • the transfer of energy onto a system (application of force that moves energy into the direction of that force)

• heat engine

  • a system that transfers energy in the form of heat that transforms that heat energy to do work

• (1st law) the change in total energy depends on energy lost or gained by the system and work done or by the system

• triangle U = Q+W (technically minus because any energy transfer or work will be negative)

• triangle U

  • change in internal energy

• Q

  • energy absorbed

• W

  • work (work and heat are measured in J)

• As temp of a gas increases

  • volume (space gas takes up) increases , so gas does work on its surroundings when temp is increased

• tectonic plates

  • pieces of the lithosphere that move around on top of the asthenosphere

• Rocks closest to the mid ocean ridge are______ and as you move from the ridge rocks get _____ implying that crust is being ______ at mid ocean ridges

  • youngest, older, produced

• Why do the properties of rock change as temperature and pressure increases?

  • The particles in the rock are excited due to the temp increase, loosening them and they become more flexible, it changes states into magma

As most solid materials undergo melting, the particles in the material ____ thus the material ______ and its density ______ therefore this position of the material will ____ relative to the surrounding material.

spread apart, expands, decreases, rise

P waves (primary waves)

longitudinal waves (slinky) that make vibrations in the direction of travel, forming areas of compression and distillation, travels through solids, liquids, and gases

S waves (secondary waves)

transverse waves (right angles), their vibrations are at right angles to the direction of travel, only travels through solids

Lithosphere and athenosphere

includes the crust: the outermost layer, mostly solid rock, tectonic plates move leading to volcanic activity

lower mantle

mostly solid, mantle convection causes the plate movement above

outer core

liquid

inner core

solid under extreme pressure (density increases as you go deeper)

seismograph

instrument that detects and records seismic waves

seismograms

the recordings made by seismographs that identifies the waves produced by earthquakes

solid chunks of mantle picked up to the surface in volcanic eruptions

mantle xenoliths

meteorites

have a similar composition to earth layers, metallic meteorites containing mostly iron which may have a similar makeup to earths core

Scientists use ______ to infer what is happening deep inside earth by conducting lab experiments to observe how rocks behave under high pressures and temps

diamond anvils, and for the solid inner core, computer models

Most energy transfer within earth happens due to

convection (mostly in athenosphere and lower mantle prompting plate movement)

Earth's core is hotter than the mantle so we can assume heat is transferred from the core to the mantle via

conduction

When two plates move toward each other and one plate is much denser than the other, the ____ plate sinks beneath the other into the athenosphere. This forces the less dense rock in the athenosphere to rise

denser

Energy flows from the core towards the surface due to ____ differences

temperature

Energy moves through the lower mantle and athenosphere as rock flows due to _____ differences. This type of energy transfer is called ____

density, convection

Wherever particles of different temps come into contact ______ transfers energy from warmer to cooler particles. It can be assumed that this occurs in the lower mantle, athenosphere, and lithosphere because they are all _____

conduction, solid rock

mantle convection

the pattern of motion in which mantle rock is colder and denser and sinks, pushing up warmer and less dense rock

Subduction

when tectonic plates move towards each other and the denser plant sinks into the mantle beneath the lesser dense plate. this forms deep sea trenches, and the subducted plate melts to form volcanic magma

slab pull

the gravitational force on the subducting edge of the plate, pulling the rest of the plate along with it

slab suction

when subducting plates indirectly exert a force on the overriding plate. As the subducting slab descends it pulls the overriding plate towards itself.

Mid oceanic ridges

mid ocean mountain ranges that can be thousands of meters higher than the sea floor where gravity pulls new formed rock from eruptions downhill, producing an outward force called ridge push (negligible in plate motion)

other factor that contributes to speed and direction of plates

friction

earthquakes mostly occur at

oceanic trenches that run along the boundaries where denser oceanic edges or lithosphereic plates sink beneath less dense plates

geophysicist

Studies processes that change and shape the Earth with electrical, seismic, and magnetic techniques

seismologist

studies earthquakes and seismic waves and how they relate to geology and earth as a whole

marine geophycisists

use different technologies to map the sea floor and understand the area beneath it

diamond anvil

crushes sample rocks between two diamonds, sometimes uses lasers, simulates temps and pressures materials may experience closer to the core

Conduction occurs

the transition in between the different layers of the earth, wherever there is solid rock through and through such as the inner core, lower mantle (sometimes/ oobleck), and lithosphere

convection occurs

In the more liquid or moldable layers such as the outer core, sometimes lower mantle, and athenosphere

layers in order

lithosphere, athenosphere, lower mantle, outer core, inner core

intensive/extensive in the earth

• Intensive

  • does not depend on the amount of a substance present, temp, pressure, density, boiling and melting points

• extensive

  • depends on the amount of a substance present, mass, volume, energy, heat capacity

geothermal energy

• Geothermal power plant

  • a plant that uses Earth's internal heat to generate electricity

• turbine

  • part of generator that produces electrical energy

• dry steam plant

  • uses steam from underground geothermal sources to turn a turbine (steam to turbine)

• flash steam plant

  • draws liquid from geothermal source, uses pressure to convert it into steam to drive a turbine (liquid to steam to turbine)

• binary cycle power plant

  • transfers energy from geothermal water to another liquid. Liquid is then converted to steam to drive the turbine (underground water to other body of water to steam to turbine)

• geothermal energy

  • energy from an underground source

• geothermal heat pump

  • uses stable underground temperatures to warm and cool homes depending on the season

• How do geothermal pumps work

  • when its cold out thermal energy from the ground heats the pipes to transfer that energy to the house, vice versa when it is cold

practice Q’s

• How is the stability of a gaseous system affected by changes in the system?

• How is energy transferred within and between systems?

• How do energy and matter cycle in earths interior

• You have two flasks of water. You place a thermometer in the first flask and leave it until the temperature no longer changes. The temperature reads 100 °C. When you move the thermometer to the second flask and again leave it, it also reads 100 °C.

  • The thermometer and the second flask of water are in thermal equilibrium.

  • The zeroth law states that the two flasks are in thermal equilibrium with each other.

• Choose the correct statement as it relates to the energy of a system and a heating curve.

• A known number of moles of gas is placed in a flexible container. What will happen if some of the gas is removed from the container while the pressure and temperature are kept constant?

  • The volume will decrease.

• The kinetic-molecular theory states that ideal gas molecules do which of the following?

  • are in constant, rapid, random motion

• Two substances have the same temperature. The particles of Substance A have a slower average speed than the particles in Substance B. What can you say about the molar masses of the two substances?

  • The molar mass of Substance A is greater than Substance B.

• A puddle of water on a sidewalk evaporates in the hot afternoon sunshine. Complete the statement to describe what is happening.

  • Before the phase change, thermal energy is absorbed by the water, causing its temperature to increase

• A scientist is testing the properties of a gas. Before he performs his experiment, he wants to make claims about the way the gas will behave in different situations. Then, he will compare his claims to his results. Complete each of the claims based on evidence you gathered in this lesson.

  • When the temperature of a gas is held constant, if pressure increases then the volume decreases
    

  • When the volume of a gas is held constant, if pressure increases then the temperature increases
    
    

  • When the pressure of a gas is held constant, if temperature increases then the volume increases

• Solid carbon dioxide changing state to gaseous carbon dioxide is an example of

sublimation

• How are evaporation and boiling alike, and how are they different? In your answer, discuss differences in energy and differences in temperature.

• Describe kinetic-molecular theory and how it applies to the transfer of energy as an ideal gas is heated.

• During an investigation, you place a gas in a glass syringe and use a movable plunger to keep the gas inside. You then slightly warm the syringe and the gas inside, causing the gas to expand. You then observe the plunger moving slightly outward. Explain the changes you observed in the system in terms of the kinetic-molecular theory.

• What happens to a cup of water if you place it in a freezer?

  • The water transfers thermal energy to the freezer, decreasing the water's internal energy.

• During an investigation, you connect two containers by a thin tube. A stopcock keeps the tube closed. One container is empty, and the other contains a gas. What will happen if you open the stopcock to connect the containers?

  • The entropy of the gas will increase, and it will spread out to fill both containers.

• When a hot piece of metal is placed in water, thermal energy is transferred from the

  metal to the water. The average kinetic energy of the particles in the metal

  decreases, while the average kinetic energy of the water molecules

  increases. This results in a decrease in temperature of the metal and an increase in temperature of the water. According to the first law of thermodynamics, the overall change in energy must be zero.

unit 3

vocab

PROPERTIES

Elements - pure substances (single type of atom)

• Not physically/chemically broken down into another element

• NOT BROKEN DOWN/SIMPLIFIED INTO OTHER ELEMENTS

• SIMILAR PROPERTIES LIKE OTHER ELEMENTS

Metals - good conductors of heat/electricity/shiny

• Bent into thin sheets (ductile)

• Solid at room temp

• Ex: magnesium, zinc, copper

Nonmetals - poor conductors of electricity/heat

• Nitrogen, oxygen, fluorine, chlorine —> gases at room temp

• Brittle/dull —> solids at room temp

• Ex: carbon, phosphorus, sulfur, selenium, iodine

Metalloids - metal/nonmetal

• Solid at room temp

• Semiconducting

• Ex: boron, silicon

Reactivity - how readily an element combines with other elements

Noble gases - no reactivity/combining with other elements

SUBATOMIC PARTICLES

Electrons - negatively charged

Nucleus - positively charged center of the atom

Protons - positive charge equal to electrons negative charge (magnitude)

Neutrons - mass of a proton/no charge

ENERGY

Electromagnetic spectrum - radiation traveling in waves identified by wavelengths

Wavelength - distance between 2 crests

Shorter wavelength—>more energy - violet

Longer wavelength—>less energy - red

Visible light - rainbow

Absorbing energy - raised energy levels

Releasing energy - returning to normal levels

Orbits - circling the nucleus in paths

• Fixed energy

Ground state - lowest energy/closest to nucleus

Excited state - further from the nucleus

ELECTRONS CANNOT BE ON SEPARATE EMISSION LINES

• cant have 2 differing energy levels

ORBITALS

Orbital - 3D region around nucleus indicating electron location

• Filled based on amount of electron energy

Increase - more filled/stable

Decrease - less filled

1s - 2 electrons/1 sub shell

Shells - 1-7 electrons based on level

S - 1 orbital

P - 3 orbitals

2s + 2p - 8 electrons

• 2: 2s

• 6: 2P

ELECTRON CONFIGURATION

Electron configuration - arrangement of electrons

• 1s orbital must be filled before moving onto the next orbital

• 1s

• 2s

• 2p

• 3s

• 3p

ELECTRON-DOT NOTATION

Valence electrons - outermost shell/level of nucleus

• part of most chemical reactions

1. Place dot based on amount of valence electrons/level

Octet - full electron shell around the nucleus (8 valence electrons)

• Carbon: 6 electrons —> 2 electrons in 1s, 2s, 2p (4 valence electrons as it does not have 8)

ATOMS

• Protons # determines amount of electrons

Atomic # - # of protons

• Neutral: proton=electron

Mass # - protons+neutrons in nucleus

Isotopes - different mass #’s/nearly identical chem. Properties

Unified atomic mass unit (u) - mass of one proton/neutron

• 1/12 mass of a common isotope —> 12u

MASS SPECTROMETRY

Mass spectrometry - measures mass of atoms

EXPERIMENTS

Cathode ray - discovered electrons

• Deflection towards positive plate at large angles

• Electron didn’t account for atoms mass

Plum pudding - electrons balanced in a mass of positively charged material

• Additional mass of atom

• Not accurate

Gold foil - alpha particles passed through foil/some deflected

• Most of the atom was empty space

• Found the nucleus/accounts for atoms mass

Flame test - produces flames of different colors

• Light —> electromagnetic radiation

• Wavelength - length of 2 crests

• Shorter - more energy (violet)

• Longer - less energy (red)

• Released - returning to normal energy levels

• Absorbed - raising energy levels/further from nucleus

Emission line - spectral lines of hydrogen atomic emission spectrum

• Can’t jump between lines of energy

• Absorb

• Release

• Interference - waves overlap —> add/cancel each other out

Double slit - light is diffracted interference occurs

• Light behaves like a wave

Exploration 1: Making predictions using the periodic table

• Dmitri Mendeleev —> organized periodic table

  • arranged by increasing atomic mass

  • left gaps for future elements based on predictions

    • Ex: predicted gallium and germanium

  • periodicity - repeating pattern of properties

• (1913) Henry Moseley - atomic #

  • number of protons in an atom

• periodic law - chemical/physical properties repeat with increasing atomic #

• period: row

• group: column

  Properties

• metals - solid at room temp, shiny, ductile, malleable, good conductors of heat/electricity

• nonmetals - less malleable, dull, brittle, less conductive

• metalloids - semiconductors

• noble gases - no charge/reactivity

  

• group 1 and 2 - alkali/alkaline earth metals

• group 3 - 12 - transition metals

• group 17 - halogens

• group 18 - noble gases

  patterns in chemical properties

• valence electrons - outermost orbitals of an atom

  • most easily gained/lost

  • # of valence electrons influence location on periodic table

  • shells of noble gases:

    • all electrons paired

    • filled with electrons

Exploration 3: Patterns in ionization energy

• ionization energy - energy required to remove an electron from a neutral atom

  • produces a charged atom - ion

  • force is greater on inner electrons

    • closer to the nucleus partially shield outer electrons from positive charge

    • repulsive force between them —> pushes outer electrons forward

    • valence electrons need less energy to break free

• depends on net force keeping the valence electrons in the atom

• Shielding effect: less energy for ionization —> greater shielding effect in valence electron level of orbital

Exploration 4: Patterns in Atomic Size

• Atomic radius - half the distance between the nuclei of identical atoms

  • pico meters: 1×10^-12 meters

  • X-ray/spectroscopy

  • Electron cloud - area surrounding nucleus

  • Charge increases along a period

  • Decrease in atomic radii

  • Increase of atomic radii - down a group —> higher energy levels —> looser electrons being held in the nucleus

• Metals - more reactive

  • larger atomic radius/outer electrons are loose—> greater attraction

• Nonmetals - smaller atomic radius/tightly bound electrons

Exploration 5: Patterns in Electronegativity

• compounds formed: gain/lose/share electron

• Stronger atom attracts a smaller one more strongly

  • ex: a boy asks girl bc he has a crush

• Electronegativity - measure of attraction for an atom it shares a molecule with

• Larger radius - weaker attraction (distance=larger) —> more protons

• Smaller radius - stronger attraction (shorter distance)

  

practice Q’s