Chemistry - Unit 2: Atomic Structure & Quantum Theory

Dalton Model

atom is a solid sphere

Thompson model

atom has electrons

Rutherford model

model with nucleus

Bohr model

each energy level is a ring

Maximum capacity for an energy level

2n²

Excited state

electron is in a higher energy level than normal

ground state

electrons are in the lowest available energy levels

line spectrum

individual lines of color seen for an element when electrons return from excited to ground state; unique to each element

relative mass of protons

1 amu

relative mass of neutrons

1amu

relative mass of electrons

1/2000 amu

z

Atomic number - number of protons in the nucleus of an atom

A

mass number - total number of protons and neutrons in the nucleus of an atom

ion

an atom with an imbalance of protons and electrons

isotope

the same type of atom with a different mass number

relative abundance

weight put into each stable isotope of an element

electromagnetic wave/particle duality

the idea that light is both a wave and a particle (photon with no mass)

Crest

the peak of an electromagnetic wave

Trough

the bottommost point of an electromagnetic wave

amplitude

the height of an electromagnetic wave

wavelength

the distance between 2 adjacent crests or troughs in an electromagnetic wave (λ)

frequency

number of crests that travel in one second (ν)

speed of light

c = 3 × 10⁸ m/s

Planck’s constant

h = 6.63⁻³⁴ Js

How to find speed of light

c = λν

how to find energy in an electromagnetic wave

E = hν

Electromagnetic spectrum

• Radio waves

• Microwaves

• Infrared light

• Visible light

• Ultraviolet light

• X-rays

• Gamma rays

wavelength decreases, freq. and energy increases

Quantum model

current model of the atom that states that an electron can be in multiple locations at the same time. Energy levels are not dependant on location

Heisenberg Uncertainty Principle

it is impossible to know both the location and velocity of an electron at the same time. An electron has wave/particle duality

Quantum numbers

n, l, m, s

n (quantum number)

principle energy level

l (quantum number)

azimuthal sublevels s, p, d, f determined by n - 1

m (quantum number)

magnetic orbitals (all integers with a distance of l from 0

s (quantum number)

spin of an electron (either +1/2 or -1/2)

orbital

can hold 2 electrons (s - 1 orbital, p - 3 orbitals, d - 5 orbitals, f - 7 orbitals)

Electron configuration

arrangement of electrons in an atom/ion

orbital diagram

shows how electrons are arranged in orbitals

coefficients of electron configurations

energy levels (max 7)

aufbau principle

electrons must be placed in lowest available energy firstd

pauli exclusion principle

paired electrons in an orbital must have opposite spinhu

hund’s rule

electrons have to have parallel spins before pairing up

core electrons

interior electronsva

valance electrons

outermost electrons (have highest coefficients)