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.
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
First to say there were many kinds of atoms, which he called elements. Atoms are never created or destroyed in an experiment.
Atoms are composed of positive and negative charges.
Calculated the charge of an electron.
All of the positive charge in an atom was concentrated in the center and that an atom is mostly empty space.
Energy changes do not occur smoothly but rather in small specific steps.
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.