Honors Chem Unit 2- Atomic Theory/Periodic Table

atomic number is the same as

number of protons

mass number is the same as

number of particles in the nucleus

protons are

positive

electrons are

negative

neutrons are

neutral

atomic number goes on ____ and mass number goes on _____

top, bottom

the number of __ determines what element a particle is, the number of _ determines what isotope of an element, and the number of —- determines the particle’s overall charge

Protons, neutrons, electrons

Empedocles

believed all matter was made up of 4 elements (earth, fire, wind, water)

Democritus

believed all matter was divisible into individual particles and that atoms combined in diff ways

John Dalton

Scientificially supported atoms, all atoms for the same element are alike

Law of Definite Composition

A compound contains 2 or more elements in a definite proportion

Law of Multiple Proportions

elements combine in different ratios to produce multiple compounds

JJ Thomson

discovered electrons, atoms are now divisible, figured there must be a positive charge since electrons are neutral.(plum pudding model)

Ernest Rutherford

protons are packed in the center or nucleus of the atom, atoms are mostly empty space, electrons move in orbits like planets around the sun (nuclear model)

Niels Bohr

Studied line spectrum of elements, modified solar system model into Bohr model, only certain, specific orbits are possible, quantized energy levels.

Erwin Schrodinger

based on mathematical probability of finding electrons, electrons located in clouds or orbitals of various shapes- s, p, d, f; quantum mechanical model

James Chadwick

discovered neutron

how many orbitals are in a 2p sublevel

3

how many orbitals are in a 3s sublevel

1

how many orbitals are in a 2nd level

4

how many electrons in a 3p sublevel

6

how many electrons in a 5s sublevel

2

how many electrons in a 3rd level

18

what is the mass of an atom measured in

amu

(n) principle quantum number

energy level of electron, larger n = more energy, can be any positive integer

(l) angular momentum quantum number

indicates orbital shape l=0 is s, l=1 is p, l=2 is d, l=3 is f, possible values are any integer from 0 to n-1

(ml) magnetic quantum number

indicates spatial orientation of an orbital, possible values anywhere from -l to positive l

(ms) spin quantum number

electrons can have 2 possible “spins”, possible values are positive ½ or negative ½

periods

horizontal rows (excluding f-block) there are 7 total in periodic table

families

columns, 18 total

Dmitri Mendeleev

recognized trends in the elements and published an accurate table of them

alakai metals

first group/family on periodic table

alakine earth metals

2nd group/family on periodic table

halogens

second to last group/family on periodic table

noble gases

last group/family on periodic table

metalloids

kind of diagonal and ambigious lowkey

diatomic gases

only really exist in molecular form not pure atom

atoms get _____ as you move down a family (column)

larger!!! because electrons are in energy levels further from the nucleus

atoms get _______ as you move across a period (row)

smaller!!!!! bc positive charge of nucleus pulls valence electrons in tighter (more effective nuclear charge)

ionization energy

energy needed to remove a valence electron

elements with lower ionization energy are _____ reactive

more!!!

when you move down a family (column), ionization energy______

increases!!!!

when you move across a period (row) ionization energy _____

decreases!!!! until electrons begin to pair up (they don’t like that and wanna push away)

quantum

specific amount

ground state

lowest energy state for electron

excited state

highest energy state for electron

photon

packet of light energy

aufbau principle

electrons fill lowest energy levels first

Hund’s rule

electrons don’t like to pair up unless they have to

Pauli exclusion principle

only 2 electrons per orbital

valence electrons

electrons in the highest energy levels or unfilled sublevels

plank’s constant

6.63 × 10 ^-34