Chemistry - the Atom

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average atomic mass unit

average atomic mass unit

amu

molar mass unit

g/mol

Erwin Schrodinger

quantum mechanical model of the atom, electrons don't always exist, it's impossible to know speed + location of electron

James Chadwick

discovered the nuetron

quantization

the concept that energy can occur only in discrete units called quanta

Niels Bohr

determine energy is quantized, electrons exist at discreet energy levels (bohr model is useful but wrong)

anion

a negatively charged ion with too many electrons

cation

a positively charged ion with too few ions

ion

atoms of the same type and have the same mass, BUT there is a difference in the number of protons or electrons

isotope

atoms of the same type with different numbers of neutrons

what does n stand for?

the charge (if the protons and electrons aren't the same number you put the net charge here)

what does the Z stand for?

the atomic number (number of protons)

what does the A stand for?

the mass number (protons AND neutrons)

gold foil experiment

alpha particles that were shot at gold foil were deflected when they hit the positive center of gold atoms. The nucleus was discovered as a result of this experiment.

Ernest Rutherford

using the gold foil experiment, he discovered protons and the nucleus

plum pudding model

electrons were randomly distributed within a positively charged cloud

cathode ray experiment

An experiment that showed that electrons had mass and a charge, electrons are ejected from the cathode and accelerated through a voltage

JJ Thompson

used the cathode ray tube to discover electrons

plum pudding model

used spherical model

John Dalton

John Dalton atomic theory

1. everything is composed of an atoms, they can not be created nor destroyed

2. all atoms of 1 element are identical

3. atoms of different elements are different masses and sizes

4. compounds are comprised of whole number combinations of atoms

5. a chemical reaction occurs is a rearrangement of atoms

Democritus, stated that the atom is based on what two properties?

they are indivisible and atoms of a type are all the same

Average atomic mass formula

(mass of A times percent A) + (mass of B times percent B) / 100

speed

distance / time

density

mass / volume

rows (horizontal)

periods

columns (vertical)

groups or families

s block

first two groups

p block

right six groups

d block

teen groups (middle of periodic table)

f block

bottom fourteen groups

group 1

alkali metals

group 2

alkaline earth metals

groups 3 - 12

transition metals

group 13

boron family

group 14

carbon family

group 15

pnictogen / nitrogen family

group 16

chalcogen / oxygen family

group 17

halogen family

group 18

noble gases

the s orbital shape

sphere

the p orbital shape

dumbbell

the d orbital shape

clover

isoelectronic

the same electron

why is chromium an electron configuration exception?

the electron can be spread out more evenly (memorize the configuration)

why is copper an electron configuration exception?

the 1st set of electron must be paired up so 3d has more room than 4s (memorize the configuration)

Aufbau Principle

electrons must fill the lowest energy level first

Hund's Rule

electrons will spread out across all available energy levels before pairing up

Pauli Exclusion Principle

that no two electrons can be the same (have the same quantum numbers)

what does the n quantum number stand for

the principal quantum number (it is equivalent to the energy level of the electron)

the electromagnetic spectrum from high energy to low energy

gamma ray - xray - ultraviolet - visible - infrared - microwave - radio

photon

a particle that represent a quantum of light