Positions of electrons in relation to the nucleus is described by quantum numbers.

Identity of an atom is determined by the # of protons in nucleus.

Isotopes - atoms of an element with different numbers of neutrons. Molar mass given on periodic table is weighted by their percent abundance

Description

When building up the electron configuration of an atom, electrons are placed in orbitals, subshells, and shells in order of increasing energy.

Within an atom, no two electrons can have the same set of quantum numbers. (regards spin)

When an electron is added to a subshell, it will always occupy an empty orbital if one is available. Electrons will always occupy orbitals singly if possibly and pair up only if no orbitals are available.

The energy of electrons is quantized (electrons can only exist at specific energy levels separated by specific intervals).

E = hv

c = vλ

where E = energy change, h = Planck's constant, v = frequency, λ = wavelength, c = speed of light

Dalton - 1) many different kinds of atoms, called elements. 2) elements combine to form compounds 3) compounsd always contain the same ratios of elements.

Thomson - cathode experiment (atoms are comprised of positive and negative charges

Millikans Experiment - plum pudding model of atom

Rutherfords Experiment - gold foil (most of atom is empty space!)

Bohr model - using quantum theory, electrons orbit nucleus at fixed radii.

Heisenberg Uncertainty Principle - cannot know position and momentum of electron at the same particular instant

de Broglie hypothesis: all matter exhibits wave characteristics λ = h/mv

Atomic Structure and Periodic Table

4 of them:

Shell - to describe size of orbital

Subshell - to describe shape of orbital

Orbital - to describe orientation of electron orbital

Spin

More info

The following increase as you go:

Atomic Radius: right to left, top to bottom

Ionization Energy: right to left, bottom to top

Electron Affinity: left to right

Electronegativity: left to right, bottom to top

D - elements that have all electrons spin paired. All of their subshells are completed. P - do not have all their electrons spin paired. Strongly affected by magnetic fields.

Is 4 lozers

Description it works well.