AP Chemistry Atoms
Terms
undefined, object
copy deck
-
Quantum Numbers:
n= ?
What does it describe? -
n= 1,2,3...
Shells, higher shell number means a greater distance away from nucleus. -
Quantum Numbers:
l=?
what does it describe? -
l = 0,1,2,n-1
Angular momentum quantum number, shape of electron's orbital. -
Quantum Numbers:
m(l)= ?
What does it describe? -
M(l) = ...-L,-1,0,1,L..
magnetic quantum number, orientation of orbitals in space.
s-> L=0
p-> L=1
d-> L=2 - Aufbau Principle
- Electrons placed in orbitals, subshells, and shells in order of increasing energy
- Pauli Exclusion Principle
- Within an atom, no two electrons can have the same set of quantum numbers.
- Hund's Rule
- Electrons always occupy an empty orbital first...singly, then pair up only if no empty orbitals are avaliable.
- Formula: Energy of an Electron
- E(n) = (1/n^2)(-2.178x10^(-18)) joules
- Electromagnetic radiation
- Electrons jump to higher energy levels, when drop, it gives off energy in the form of this radiation.
- Formula: Energy and Electromagnetic Radiation
- delta E = hf = hc/lambda
- planck's constant
- 6.63x10^(-34) Joule-sec
- speed of light
- 3.00x10^8 m/sec
- Dalton's elements
- first to say that there are many different kinds of atoms, which combine to form compoundds and same ratio of elements
- Dmitri Mendeleev and Lothar Meyer
- development of periodic table
- Thomson's Experiment
- deflection of charges in a cathode ray tube, atoms are composed of positive and negative charges. Plumb pie model.
- Milikan's Experiment
- oil drops in electric field to calculate charge of an electron
- Rutherford's experiment
- fired alpha particles at gold foil. Positive chare concentrated in center.
- Max Planck
- electromagnetic energy is quantized, so energy changes do not occur smoothly but in small specific steps.
- Bohr model
- electrons orbit at a specific fixed radii, only works for hydrogen
- Heisenberg uncertainty principle
-
impossible to know both the position and momentum of an electron at a particular instant.
An electron orbital is a probability function describing the possibility of an electron at a location. - de Brodlie hypothesis
- all matter has wave characteristics.
- De Broglie equation
- lambda= h / mv
- Atomic radius...
-
decreases across a period
increases down a group - Size of ions...
-
Cations smaller than atoms
Anions bigger than atoms - Ionization energy
-
Energy required to remove an electron from an atom
increases across a period
decreases down a group - Electron affinity
-
measure of the change in energy of an atom when electron is added.
Energy put in when atom becomes less stable...vice versa - Electronegativity
-
how strongly nucleus of an atom attracts electrons of other atoms in a bond
Increases across period
Decreases down a group