Modern Atomic Theory

Electromagnetic Light Spectrum

radio waves, micro waves, infrared radiation, visible light, ultaviolet rays, x-rays, gamma rays

h in E=hv

6.626×10^-34 Js

speed of light ( c )

3×10^8 m/s

conversions from nm to m

10^9nm/1m

Avogadro’s Number

6.022×10^(23)

Hund’s Rule

every electron in an orbital must be fileld at least once

Pauli’s Exclusion Principle

orbital can hold 2 electrons; must have oppostive spins

Aufbau Principle

electron occupies orbitals from lowest to highest energy levels

Visible Light Spectrum

red, orange, yellow, green, blue, indigo, violet

Democritus

FIRST - matter is made up of fundamental particles, called atoms, that are indivisible and invisible.

Dalton

SECOND - 1st evidence that atoms exist (six principles) + Democritus was wrong  and that atoms can be broken down into smaller parts 

Thomson

THIRD - discovered electrons, atoms must consist of smaller particles of positive and negative charges (plum pudding)

Rutherford

FOURTH - atom is made of around 90% empty space and discovered nucleus and its positivity

Chadwick

Discovered the neutron has no charge

Bohr

FIFTH - predict likely electron positions in his planetary model, proposed ground state and excited state, electrons have a quanta of energy

Planck

SIXTH - Energy is quantized, specific energy levels, electrons cannot exist in between energy levels, energy is not continuous

deBroglie

SEVENTH - Electrons must move in paths not circular orbits 

Heisenberg

SIXTH - can not know both electron speed and its exact position simultaneously, so electrons don’t move in fixed orbits

Schrodinger

The electron moves in orbitals; predicts the probability of finding an electron at a certain location near the nucleus 

Electromagnetic Radiation

flow of energy at light speed

• electron’s excited state does not reach threshold energy

Photoelectric Effect

electrons eject from metal’s surface when light is shown

• electron’s excited state surpasses threshold energy

When solving for wavelength (lambda)

meters

When solving for frequency (v)

Hz