20 terms

Atomic Structure and the Periodic Table

Quantum Numbers
Shells: n = 1,2,3...
Subshells: l = 0,1,2...
Orbitals: ml = ...-1,0,1...
Spin: ms = (1/2), - (1/2)
The Aufbau Principle
When building up the electron confuguration of an atom, electrons are placed in orbitals, subshells and shells in order of increasing energy.
The Pauli Exclusion Principle
Within an atom, no two electrons can have the same set of quantum numbers. Therefore, each electron in any atom has its own distinct set of four quantum numbers.
Hund's Rule
When an electon is added to a subshell, it will always occupy an empty orbital if one is available. Electrons will always occupy an orbital singly if possible and pair up only if no empty orbitals are available.
Elements with all their subshells completed.
Elements with not all of their subshells completed
Energy of an Electon
Energy of electrons is quantized.

En = (-2.178 X 10^-18) / n^2

En = energy of electron
n = principal quantum number of the electron
Energy and Electromagnetic Radiation
When atoms absorb energy in the form of electromagnetic radiation, electrons jump to higher energy levels.

Delta E = hv = (hc) / lambda

Delta E = energy change
h = Planck's constant, 6.63 X 10^-34
v = frequency of the radiation
lambda = wavelength of the radiation
c = the speed of light, 3.00 X 10^8
Dalton's Elements
First to say there were many kinds of atoms, which he called elements.
Atoms are never created or destroyed in an experiment.
Thomson's Experiment
Atoms are composed of positive and negative charges.
Milikan's Experiment
Calculated the charge of an electron.
Rutherford's Experiment
All of the positive charge in an atom was concentrated in the center and that an atom is mostly empty space.
Quantum Theory
Energy changes do not occur smoothly but rather in small specific steps.
Bohr Model
The use of quantum theory to predict that electrons orbit the nucleus at specific fixed radii
The Heisenberg Uncertainty Principle
It is impossible to know both the position and the momentum of an electron at a particular instant.
The de Broglie Hypothesis
Lambda = (h) / mv

Lambda =wavelength associated with a particle
m = mass of particle
v = speed of partiicle
mv = p = momentum of the particle
h = Planck's constant, 6.63 X 10^-34
Move from left to right across periodic table
Atomic Radius decreases
Ionization Energy increases
Electronegativity increases
Moving down a group
Atomic Radius increases
Ionization Energy decreases
Electronegativity decreases
Postively charged ions that are smaller than atoms.
Negatively charged ions that are larger than atoms.