Chem lect 1

two or more atoms of same element but different numbers of NEUTRONS

A = protons + neutrons

Z= number of protons

IDENTITY number of element
(mass number can change= isotopes bc neurons; electrons too obv)

Z= number of protons

IDENTITY number of element
(mass number can change= isotopes bc neurons; electrons too obv)

6.022x10^23 (amu=1gram)

Loose hold on electrons
ductility
malleability
thermal and electrical conductivity
characteristic luster

typically form IONIC oxides (BaO)

generally have lower melting points than metals

diverse group

form COVALENT oxides (CO2)

alkali metals
alkali earth metals
transition metals
halogens
noble gases

small make strong pi bonds (p-orbitals overlap) BUT no d orbitals so less bonds

amount of charge felt by a 2nd electron due to shielding of 1st electron

increases left to right and top to bottom on table

energy needed to detach an electron from a nucleus

from neutral atom = 1st ion E

increases from left to right and bottom to top on table

tendency of an atom to attract an electron in a bond it shares with another atom

increases from left to right and bottom to top on table

undefined for noble gases

willingness of an atom to accept an additional electron (or the energy released when electron is added)

increases from left to right and bottom to top

point where energy level is the lowest

2 atoms will only form a bond if their overall energy level is lowered

10^6

10^3

10^-1

10^-2

10^-3

10^-6

10^-9

10^-12

10^-15

phys: maintains molec structure - melting

chem: change in molec structure

actual yield (what end up with in real rxn)/
theoretical (when rxn runs to completion)
x 100= percent yield

"percent of the theoretical yield we were able to obtain in the experiment"

Ionic = electrostatic forces (salts)

Metallic = delocalized electrons (single metal atoms together)

Network covalent = polar and nonpolar (diamond)

Molecular = intermolec. bonds (ice; less common)

rapid cooling= amorphous
slow cooling = crystalline

principal (n)=shell level
azimuthal (l) = subshell; n-1 (s,p,d,f)
magnetic (m) = precise orbital in subshell (+l to -l)
electron spin (ms)= +1/2 or -1/2

no two electrons in the same atom can have the same four quantum numbers

n^2

inherent uncertainty in the product of the position of a particle and its momentum, on the order of plancks constant

xp~h

6.63x10^-34 J s

spider

orbitals at same energy level
ie 4s and 3d

electrons will not fill any orbital in the same subshell until all orbitals in the subshell contain at least one electron;
unpaired electrons have parallel spins

electromagnetic energy is quantized

change in E=hf

Einstein demonstrated one-to-one photon- electron collision causes emission of electrons

need to worry about frequency not number of photons

min amount of E required to eject an electron is work function of metal

Kinetic enegy of ejected electron (KE) is hf-work function