crookes first, thomson around 1897,

1. glass tube with limited amount of gas in it, hooked up to an electricity source.

2. produced a florescence.

3. crooked thought it was radiation of some type and called fluorescence "cathode rays"

thomson discoverd that the cathode (f beam) were attracted toward a positively charged electrode, they are negative. They are particles because magnetic will only change direction of particles

disproved Dalton;s theory that atms are indivisible.

he cam up with plum pudding modle.

Rutherford

1911

what did he do?

aimed alpha particles at a thin sheet of gold foil

predictd they would go right through tfoil and most did, but some delected at various angles.

1. the atom is mostly empty space

2. a tiny, dense core in atom, this is why some deflected.

3. the core is positive b/c alpha were not attracted to it.

Rutherford

1911

conclusion

1. the atom is mostly empty space

2. a tiny, dense core in atom, this is why some deflected.

3. the core is positive b/c alpha were not attracted to it.

credited with discovering nucleus, positive, most of mass of atom.

Bohr

1913

Findings

improved rutherford's model

1. answered question- why arent electrons pulled into positive nucleus if opposites attract?

2. bohr suggested that electrons are in orbit(now called energy levels) around the nucleus

3. Planetary atomic model

4. electrons located in orbits which ar different distances from nucleus

5. ELectrons have a certain amount of fixed energy, which prevents them from spiraling toward nucleus.

a. the futher the electron is from nucleus, the greater the energy of it

b. an atom is in ground state when all electrons occupy lowest energy levels (most stable)

c. electrons can absorb energy from outside source. When this happens, they move to higher enery levels, but are unstable.

particle nature of light

plancks constant: 6.626 x 10^-34 J*s

used in E= hv

De Broglie

1942

thought there was wave nature of particles

• electrons have wave properties as wel as particle
• electrons are a "blur" or space filling

Heisenberg

1927

uncertainty principle

looks at electron as Particle

• impossible to know exact location and velocity of electron
• location is determined by bombarding electrons with photons. the collision changes the velocity of the elevtron. Opposite is also trye, trying to measure velocity will change its position.

Schrodinger

1926

wave equation; probabillity of finding an e-

looks at electron as wave

developed wave equation which could determine the probability of finding elevtrons in certain areas. they do not follow strict paths (bohrs model did)

calculations

lambda= h/ mass velocity

c=lambda nu

E= h nu

• atoms with same number of protons and different number of neutrons
• disproved point in dalton's theory

• charged particle
• Ca²⁺ cation positive loose 2 els
• F^- anion negative increase 1 el

• gives element identity
• # of protons
• represented by z

• number of protons and neutrons
• represented by A
• neutral
• A/Z X

Protons: nucleus, positive, 1

Neutrons: nucleus, neutral, 1

Electrons:outside nucleus, negative, 0

groups are vertical

periods are horizantal

Location

Alkali metals, alkaline metals, noble gasses, halogens, transition metals, main group elements, metals, metalloids, nonmetals

quantum number 1

represents:

which describes:

how many?

symbol:

values:

represents: energy level

which describes: relative size of electron cloud

how many? 1-7

symbol: n

values: positive integers

quantum number 2

represents:

which describes:

how many?

symbol:

values:

represents: sublevels

which describes: shape of electron cloud

how many? 4 spdf

symbol: l

values:0 -> n-1

other info: energy level = # of sublevels

quantum number 3

represents:

which describes:

how many?

symbol:

values:

represents: orbital

which describes: orientation of electron cloud

how many? s -1 p-3 d-5 f-7

symbol:m_l

values: -l to l

other info: orbital -- amount of space occupied by a maximum of 2 electons.

quantum number 4

represents:

which describes:

How many:

symbol:

values:

represents: spin

which describes:direction of electron spin

how many? either clockwise or counter

symbol:m_s

values:+1/2 or -1/2

other info: electrons in the same orbital must have opposite spins

ground is stable

excited is not

atoms have no charge

ions have a charge

Na - [Ne]3s¹ 1 val e-

P - [Ne]3s²3p³ 5 val e-

Pb- [Xe]6s²4f¹⁴5d¹⁰6p² 4 val e-

Fe- [Ar]4s²3d⁶ 2 val e-

exceptions to d⁴ and d⁹

which elemts is this for?

elements: chromium, molybdenum, copper, silver, gold

d⁴ -> d⁵

d⁹ ->d¹⁰

have similar electron configurations

had negative charge particles

negative b/c drawn to positive

positive beam different defractions

not the same mass