ECU CHEM 1150 Test 2

Standing Waves

remain contained in space, fixed at two points

Vibrating Strings

energies increase with the number of half wavelengths, n

Blackbody Radiation

absorbs all wavelength; thermal equilibrium → must emit radiation at same rate; emit continues spectrum

Bohr Model (circular orbitals) what was right?

quantized energy levels; emission spectra from energy level transitions; concept of nuclei

When e- energies are quantizied, this results in

energy levels

l ( angular momentum quantum number)

can take on values =0,1,2,3,4…. =n-1; specifies shape

n ( principal quantum number)

as it increases, E increases; aka shell

Heisenurg uncertainty principle

Impossible to determine simultaneously and exactly both momentum and position of a particle

ml (m sub l - magnetic quantum number)

specifies spacial orientation; can be -l, -(l-1),…0…(l-1), l

ms (m sub s - spin quantum number)

e- acts as though it is spinning; like a tiny magnet; +1/2 or -1/2

Pauli Exclusion principle

no two e- in the same atom can have the same 4 quantum numbers

shielding

screening e- from full effect of nuclear charge

Effective nuclear charge (Zeff)

the inner e-’s effectively shield outer e- from nuclear charge

Penetration

less shielding; would experience full charges; lower PE

Aufbau’s Principle

build e- configuration from low E to high E

Hunds Rule

When filling degenerate (same energy) orbitals, fill them singly first with parallel spins

e- configuration of ions: cation

one or more e- removes

e- configuration of ions: anion

one or more e- gained

e-configuration of ions: Main group elements

e- added last are first to be removed

e- configuration of ions: transitions metals

e- are removed from highest s orbital first, then d electrons

VDW radius

non-bonded solid; distance b/w centers is twice the radius

Covalent radius

½ the distance b/w 2 bonded atoms (smaller than vdw)

Atomic Radius

average bonding radius

2 guiding rules for atomic radius

increases as you go down group; decreases as you move across a period

Ionization energy

energy to remove most loosely bound e- from ground state

Period trends of Ionization energy

Increase across and up; as atomic radius increases, IE should decrease

Electron affinity

energy charge associated w/ gaining an e-

Periodic Trends of EA

increase left to right, increase bottom to top