atomic structure

Thomson

1897 found the electron

nicknamed the “plum pudding”

Rutherford

1918 found the proton

also gold foil experiment

chadwick

1932 found neutron

electron location

empty space (electron cloud)

proton location 

in nucleus 

neutron location 

in nucleus 

electron actual mass

9.1 × 10 e -28 g

proton actual mass

1.672 × 10 e -24 g

neutron actual mass

1.674 × 10 e -24

electron amu

0.0006

proton amu

1.00

neutron amu 

1.00

electron charge

-1

proton charge

+1

neutron charge

0

Bohr

1913- attempted to explain the location of the electron

Isotopes

atoms with the same identity but different mass.

• same number of protons

• different number of neutrons

atomic emission Spectra

set of frequency of waves emitted by atoms

electrons

naturally in a ground state (lowest energy)

closest to the nucleus

Democritus

matter is composed of tiny particles called atoms

Aristotle

disagreed with the idea of atoms

believed in the 4 elements

Define atomic number

the number of protons in the nucleus.

H. Mosley discovered each element contains a unique positive charge.

determines the place for each element on the periodic table.

mass number

total number of protons and neutrons found in the nucleus.

REMEMBER! ALL of the mass of the atom is found in the nucleus

BAND-AID POINT

internal electrons remain the same

cd[kr]5s²4d^10

electron dot

only highest level electrons as a dot value electrons.

8 maximum-called an octet can be predicted by location

electron configuration

number of electrons in the sublevel as a transcript

1s² 2s² 2p^4

orbital notation

shows every electron with an arrow

P orbital

“dumbbell orbital” duel loaf always opposite

S orbital

spherical orbital

F

7 spots can hold 14

D

5 spots can hold 10

P

3 spots can hold 6

S

1 spot can hold 2

wavelength

Lamba usually expresses in m,cm,nm

frequency

number of waves that pass a point per second or given in time

speed

C- 3.00×10^8 m/s

C is a constant so it cant be calculated

all electromagnetic waves travel at the speed of light

X-ray

penetrate the skin only, it cant go any deeper to the bones

cosmic rays

because they're shorter they have a higher energy level

gamma rays

often used in cancer treatments more frequently brain cancers

transverse wave

travel at the speed of light

electron configurations

1.) The arrangement of electrons in an atom.

2.) lowest energy and most stable.

3.) follows 3 basic rules of predicting arrangement.

rules of electron arrangement 1.)

aufbau principle- each e occupies the lowest energy orbital.

Each sub level has a different energy state

e^- within an energy level fill in sub level order S,P,D,F

The energy levels overlap so a guideline is needed to establish sub level order

rules of electron configuration 2.)

pauli exclusion principle- an atomic orbital contains a maximum of 2 e^-

the 2 e^- will travel with opposite spins

direction of spin will be represented by the arrows

rules of electron arrangement 3.)

Hunds rule

e^- will individually occupy equal energy orbitals before forming a pair.