Chemistry- Memorization for Midterms

What was Democritus' theory?

Atomos, the belief that eventually, particles would become too small to keep splitting apart.

Four Parts of Dalton's Atomic Theory

1. Atoms are the smallest particles you can have
2. Atoms of the same element are the same including mass
3. Atoms of different elements are different including mass
4. Atoms combine in a whole mass ratio (compound)

Updated Dalton's Atomic Theory - atoms are the smallest particles you can have

Subatomic particles are the smallest particles you can have (p, n, e)

Updated Dalton's Atomic Theory - atoms of the same element are the same including mass

Isotopes are atoms of the same element but different by mass

Law of conservation of mass expanded with Dalton's atomic theory

1. Total number of atoms is conserved
2. Total number of each type of atom is conserved

What did Thomson discover?

electrons

How did Thomson discover electrons?

He used a cathode ray tube and a magnet to manipulate the particles traveling across it

Plum pudding model

Thomson's model of the atom

What did Rutherford discover?

nucleus (protons)

What three characteristics of the nucleus did Rutherford discover?

1. It has a small volume compared to the rest of the atom
2. It is extremely dense and had a high mass
3. It is positively charged

How did Rutherford say electrons move around the nucleus?

In orbits like planets around the sun (did not say why)

What is Rutherford's atomic model?

Nuclear model

What is Bohr's model of the atom?

Planetary model

Further distance from nucleus \=

higher energy in the electron

Closer distance to the nucleus \=

lower energy in the electron

What is the ground state of an atom?

when all the electrons in the atom are in the lowest possible energy level

What is the excited state of the atom?

When at least one electron is not in the lowest possible energy level

What did DeBroglie say light acted as?

As a wave

What did Planck say light acted as?

As a particle

How does light actually act?

As both a particle and a wave

What is the electromagnetic spectrum?

all the forms of electromagnetic radiation

What is infrared light also know as?

Heat

What is ultraviolet light also known as?

UV

What is the order of visible light?

red, orange, yellow, green, blue, indigo, violet (ROYGBIV)

How are frequency and energy proportional?

Directly proportional E \= h*f

How are wavelength and frequency proportional?

Indirectly proportional c \= λ*f

How are energy and wavelength proportional?

Indirectly proportional (Higher frequency and energy means a smaller wavelength)

What is a bright line spectra?

A way of representing which types of light are being given off by an atom

What do the lines on a bright line spectra indicate?

The movement of an electron up and down energy levels which is picking up and then giving off discrete energy packets.

What can you do with a bright line spectra?

You can identify an atom because each atom has a distinct bright line spectra

What was Dalton's atomic model?

Solid sphere

What was Erwin Schrodinger's atomic model?

Quantum model

What is Coulombic force?

The attraction or repulsion between charged particles

What are the two major factors that affect Coulombic force?

1. Charge on the nucleus (number of protons)
2. Energy level of the electrons (distance from nucleus)

Trend for Coulombic force down a group

It decreases

Trend for Coulombic force across a period

It increases

Why does atomic radii decrease across a period?

Higher Coulombic force means everything is held closer together

Why does atomic radii increase down a group?

Lower Coulomic force means the electrons are in higher energy levels and further from the nucleus

What is ionization energy?

The energy required to remove the first electron from an atom

What are the periodic trends for ionization energy?

Increases across a period and decreases down a group

Why does ionization energy follow the periodic trends it does?

Higher Coulombic force means that it is harder to remove an electron and vice versa

What is electronegativity?

The want of an electron by another atom

What is the relationship of Coulombic force to electronegativity

Higher electronegativity elements have higher Coulombic force

What is the periodic trend of electronegativty?

Increases across a period and decreases down a group

What is the definition of metal? (The one that is applicable for this subject)

A element that is likely to get rid of an electron

What is the periodic trend for metallic characteristic?

Increases down a group and decreases across a period

What other periodic trends does metallic characteristic relate to and why?

Coulombic force and Ionization energy - The lower the Coulombic force and ionization energy means that it is easier for an electron to be given off by an element which is the definition of a metal

How does ionic radius compare to atomic radius for metals?

Ionic radii is smaller

How does ionic radius compare to atomic radius for non-metals?

Ionic radii is larger (greater electron to electron repulsion)

What is the trend for ionic radii down a group?

Increases

What is a mole used for?

The measure of the amount of substance.

Why do we use moles to measure amount?

There are too many atoms in a normal amount of something so we use a conversion factor (moles) to help make the numbers easier to understand and use.

What does the mole concept allow us to do?

Measure the number of particles and the volume for gases as standard temperature and pressure (@STP)

How do you determine the correct number of significant figures in an answer?

You use the same amount of significant figures as the value given to you in the question. (Usually 3 or 4)

Be able to calculate molar mass for both elements and compounds.

\#mole = #grams / (#grams/mole)

and C6H3 = \[6(Cx) + 3(Hy)\] / #moles C6H3

Know how to use periodic table to determine electron configuration and the number of valence electrons

Electron configuration last value = row of the periodic table and the block that it is in, from there all of the previous orbitals are filled in

Number of valence electrons = column number except for d-block

Compounds with prefixes in the name

Molecular compound

What does a molecular compound not contain?

A metal element

N7S3

Heptanitrogen trisulfide

Dicarbon Hexahydride

C2H6

What differentiates an ionic compound from a molecular compound?

Ionic compound has a metal, can have poly atomic ions, and does not have prefixes in the name

Binary ionic compound

Ionic compound consisting of a metal and non-metal

Ionic compound with polyatomic ions

Ionic compound consisting of a metal combined with an ion made of multiple atoms. (Ammonium is the exception)

Ionic compound with cations with more than one charge

Ionic compound that has either roman numerals or a metal that can have more than one charge

How to determine charge of cations from periodic table

count left to right column number skipping d-block and stopping at non-metals

How to determine charge of anions from periodic table

count right to left from noble gases and stop at metals

Ba1O1

Barium Oxide

Magnesium carbide

Mg2C1

Iron (III) phosphate

Fe1(PO4)1

Cu2(CO3)1

Copper (I) carbonate

Kinetic Molecular Theory

All substance are made up of Particles (basic units) that are in constant motion (therefore has energy) and sometimes they interact/collide.

Conservation of Mass

Mass can not be gained nor lost in a physical process or chemical reaction. A more simple definition is Mass is conserved.

Conservation of Energy

Energy can not be gained nor lost in a physical process or chemical reaction. A more simple def is Energy is conserved.

Coulombic Force (Coulombs Law)

Same charge particles repel, different charge particles attract.

Physical Property

Characteristics that can be observed without the production of a new substance

Examples of Physical Properties

Color, odor, mass, density, specific heat, malleability, ductility, conductivity, melting point, boiling point, magnetism.

Chemical Property

Characteristics that describe how the substance interacts (or fails to interact) with other substances to produce new substances.

Examples of Chemical properties

flammability and reactivity

Intensive Property

Properties that do not depend on the size of the sample

Extensive Property

Properties that depend on the size of the sample

Physical Change

Particles do not change, just changing spacing or other parameters of the particles but without change of chemical properties or composition

Chemical Change

Particles do change and creates a new set or sets of particles. Products differ in chemical properties from the original substances

Four Observations of a Chemical Change

Permanent color change, Gas is generated, Energy change, Precipitate formed

How to tell a gas is formed

Odor is produced or bubbles formed

Element

Pure substance of only one type of atom

Compound

Two or more elements chemically combined in a fixed mass ratio

Mixture

A combination of two or more substances that are not chemically combined and retain original properties

Heterogeneous Mixture

Mixture where the particles are unevenly distributed and will eventually settle out. ex. paint, muddy water, orange juice

Homogenous Mixture (solution)

A mixture in which the particles are evenly distributed and do not settle or filter out. ex. saltwater, windex, dish soap

Mixture vs. Compound

1. Mixtures are not chemically combined
2. Mixtures are not in a fixed mass ratio
3. Properties of compounds differ from the original substances

Solution

A mixture that forms when one substance dissolves another.

Colloid

A mixture containing small, undissolved particles that do not settle out.

Suspension

A mixture in which particles can be seen and easily separated by settling or filtration

Tyndall Effect

The ability to see a light beam passing through a suspension or colloid because the particles are large enough to reflect light

Definition of Chemistry

the study of matter and the changes it undergoes

Pure Scientists

Observing the natural world, pure data, and science

Applied Scientists

Applying what we know to more humanistic things, man made science

Three Phases of Matter

Solid, Liquid, Gas

How do phases of matter differ?

Different levels of energy and Inter-molecular Force

What phase of matter has the highest IMF?

Solids