U2: Structures and Properties (SCH4U)

credits: sw0808

What did James Chadwick discover?

neutrons

What did Max Planck create?

quantum theory

Quantum

a small quantity

Photon

a quantum of light energy

Spectroscopy

used to analyze spectra

Bright line spectrum

bright lines produced by gas

Neil Bohr's model

energy levels, electrons are drawn in circles which is inaccurate because they move at random

Who used the word atom first?

Democritus

State John Dalton's laws

Definite composition - elements combine in a mass ratio

Multiple proportion - may be more than one mass ratio

Conservation of mass - total mass remains

Define Matter

indestructible / indivisible atoms that are different for every element

What did J. J. Thomson discover?

electrons

What did J. J. Thomson's model look like?

a raisin bun

What happened in Rutherford's gold foil experiment?

alpha particles were deflected, but it was predicted that the alpha particles would travel through the gold foil

Atomic Model - Orbits

2D path

2n^2 electrons per orbit

circular path

based on quantum number n

Quantum Model - Orbitals

3D region

2 electrons per orbital

no path

based on quantum numbers n, l, ml, ms

Principal Quantum Number - n

relative size of orbital

1 to 7

Secondary Quantum Number - l

orbital shape

0 to n-1

l = 0, s orbital, sphere shape

l = 1, p orbital, peanut shape

l = 2, d orbital, daisy shape

l = 3, f orbital, f***** shape

Magnetic Quantum Number - ml

orbital orientation

+l to -l

Spin Quantum Number - ms

spin of electrons

+1/2 or -1/2

+1/2 unpaired, counter clockwise

-1/2 paired, clockwise

Aufbau Principal

lower energy levels fill first

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

Pauli Exclusion Principal

electrons in same orbital have opposite spins

Hund's Rule

every orbital has to have 1 electron before they be doubled up

Ionic

metal + nonmetal, transfer of electrons

electronegativity difference greater than 1.7

Polar covalent

electronegativity difference between 0 and 1.7

Covalent

2 nonmetals, sharing or electrons

electronegativity difference 0

VSEPR

valence shell electron pair repulsion

linear, 180

trigonal planar, 120

tetrahedral, 109.5

pyramidal, 107.3

bent or v-shaped, 104.5

Ionic crystals

metal + nonmetal or polyatomic ion

crystal lattice structure

Metallic crystals

2 metals

electrons flow around positive nuclei, accounts for conduction of electricity

Molecular crystals

2 nonmetals

crystal lattice structure

do not conduct electricity

Covalent crystals

C, SiC, SiO2

hardest substances in existence

do not conduct electricity