Unit 2 Matter and Energy

All things around us (both visible and invisible) are classified as…

matter, energy, or both

matter

anything that takes up space and has form/shape

energy

ability to do work

there are many different forms of…

matter and energy

matter has

mass

mass

quantity of matter contained in an object

SI unit of mass is the…

kilogram (kg)

1 kilogram equals…

1000 grams

mass is a term associated with _____, but they are not strictly the same

weight

weight

force that an object exerts under gravity

gravity

force of attraction that exists between any two masses, bodies, or particles

weight is dependent on _____

gravity

as mass increases, so does the….

attraction (gravity)

acceleration of gravity (g)

objects that fall to earth do so at a constant rate

acceleration of gravity on Earth

9.8 m/s² (approx. 32 feet per second)

acceleration of gravity on the moon

1.6 m/s²

acceleration of gravity on Jupiter

24.8 m/s²

the weight of an object changes due to its surroundings, which is…

influence of gravity

T/F: mass changes due to its surroundings

false, weight does

which four elements did the ancient greeks believe made up all matter?

fire, air, water, earth

who believed that regardless of the number of times you cut a form of matter in half, you would always have a smaller piece of that matter?

aristotle

who put forth the idea that all matter was formed from different types of tiny particles he called “atomos” (Greek for indivisible or unable to be cut)?

democritus

the atomic idea of matter espoused by democritus fell out of favor because…

aristotle did not agree with it

It was not until the early 1800s that scientists began to discover that ______ were the building blocks of all matter

atoms

matter is usually a mixture of ____ or _____ substances

two, more

substances

any material that has a definite and constant composition

simple substances are…

elements

simple substances cannot….

be broken down into simpler substances by ordinary means

atoms

smallest particle of an element that still possesses its chemical property (ex: silver AG is made up of only silver atoms)

complex substances are…

compounds

complex substances

2 or more different elements chemically united (H₂O)

what are the basic states of matter?

solid, liquid, gas

solid

substances with a fixed volume and shape

in a solid, their particles are ____ _____ and ___ ____ compressed

tightly packed, not easily

solids are mostly made up of which type of energy?

vibrational

liquids

substances with a defined volume, but undefined shape

in liquids, particles are ____ ____, _____ ____ compressed, but can ___ ____ one another

slightly packed, not easily, move past

in a liquid, atoms and molecules are in

motion

liquids can take the shape of their

container

gasses

substances with indefinite volume and shape

in a gas, particles are ___ ___ apart, _____ compressible, and ___ ___ move past one another

very far, easily, can easily

in a gas, atoms and molecules move in ____ direction and _____ bump into one another

any, occasionally

gasses can be easily _____ and _____ ___ ____ of their container

compressed, take the shape

john dalton

elements differentiate from each other based on mass; atoms of a particular element react the same way chemically

dmitri mendeleev (developed periodic table of elements)

arranged the known elements in order of increasing atomic mass and on the basis of similar chemical properties

ernest rutherford

developed nuclear model of the atom

the atom has a _____ charged dense center called the _____, and is surrounded by a _____ charged cloud of electrons

positively, nucleus, negatively

niels bohr

proposed a model for the atom that is still widely used in explaining composition of atoms

atom is a mini “solar system” where electrons revolve around nucleus in fixed orbits

erwin scrodinger

abandoned the idea of precise electron orbits and replaced them with a description of the regions of space around the nucleus called “orbitals”

orbitals are _____ for location of where electrons were most likely to exist within an atom at any given moment in time

probabilities

the greatest probabilities are associated with ______ model

bohr’s

nucleus

small, dense center that contains nucleons (protons, neutrons)

orbitals (electron shells) contain…

electrons

different atoms vary in the number of ____ present

nucleons

atoms differ in the number of _____ present and the number of ____ available for the electrons

electrons, shells

protons

positively charged sub-atomic particles

the mass of protons

1.673 × 10^-27 kg

what distinguishes one element from another?

number of protons in an atom’s nucleus

neutrons

sub-atomic particles that have no charge

what is a neutron’s mass?

1.675 × 10^-27 kg (largest)

electrons

negatively charged sub-atomic particles

mass of an electron

9.109 × 10^-31 kg (smallest)

electrons are in _____ motion found in space around the nucleus

continuous

the energy level of an electron determines…

the orbital it occupies and the relative distance from the nucleus

each orbital and the electrons therein have a certain…

electron binding energy

E_b

what is the SI unit for binding energy?

electron volt (eV)

eV

energy of one electron when accelerated by one volt

1 keV amounts to how many electron volts?

1000

atoms vary in total number of electrons and orbitals present, but individual electrons in every atom have the same….

mass

quarks

sub-nuclear structures that exist in groups of 3 inside a proton/neutron

(quarks do NOT exist in an electron)

string theory

physicists believe that quarks/electrons are not particles but small loops of rapidly vibrating string-like matter

M theory

attempts to link quantum physics and relativity

nucleons (protons, neutrons) make up most of the mass of an atom since they are larger than…

electrons

neutrons are how many times larger than electrons?

1838

protons are how many times larger than electrons?

1836

the mass of the orbital electrons is disregarded when determining…

overall mass of an atom

atoms vary in mass (size) based on…

the number of nucleons present

when precision is not needed, how may sub-atomic particles be expressed rather than the kilogram?

carbon 12 atoms by using the atomic mass number (A)

since protons and neutrons are almost the same mass, what do they have a mass of? (its a number)

1

electrons are so small in relation to nucleons and contribute little to the mass of an atom. what is their atomic mass number?

0

atomic mass number (A)

mass of an atom can be expressed using this

what is the A number for an atom?

the total number of nucleons present

atomic number

number of protons in an atom that determines what element it belongs to

isotope

an atom of a particular element that differs in the number of neutrons present

isotopes would have the same ____ _____, but a different _____ _____

atomic number, atomic mass

isotopes can be man-made by ____ or _____ _____ (neutrons) to an atom’s nucleus

removing, adding particles

what is needed when removing/adding atoms to an atom’s nucleus?

particle accelerator/nuclear reactor

radioisotopes

isotopes that have unstable nuclei (either natural or man-made) and emit radiation (gamma rays/particles) from the nucleus

what is the most abundant element in the universe?

hydrogen

hydrogen has how many naturally occurring isotopes?

3

protrium (hydrogen 1)

stable isotope that is the most common form of hydrogen on earth

it makes up 99.985% of all hydrogen

deuterium (hydrogen 2)

stable isotope that is much less abundant

makes up .015% of all hydrogen

tritium (hydrogen 3)

unstable isotope that is radioactive

extremely small amounts of it exists as a result of the interaction of cosmic rays with atmospheric gasses & from being released during nuclear weapons testing

atoms must contain at least 1 energy shell (orbital) to…

exist

maximum number of shells any atom can possess is…

7

principal quantum numbers

letters or numbers to label shells

which forces maintain electrons positions and motion in orbit?

centrifugal force and electrostatic force

centrifugal force

electron tends to fly out into space

electrostatic force

positively charged nucleus and negatively charged electrons

the number of electrons present in each energy shell varies according to what?

the atoms of a particular chemical element