CHEM111 midsem test

Cathode ray tube experiment

JJ Thomson- discovered electrons and charge/mass ratio

Oil drop experiment

RA Milikan- measured charge of electron

Ernest Rutherford experiment

shot alpha particles at thin gold foil- discovered the nucleus

who discovered the neutron?

James Chadwick

quantum numbers- n

principal quantum number
n=0,1,2… infinity

determines energy and orbital radius

quantum numbers- l

orbital quantum number

l=0,1,…n-1

determines shape and name (s,p,d,f)

quantum numbers- ml

magnetic quantum number

ml= -l,…0,…+l

determines orientation/number of each type of orbital

shell

electrons with same value of n

subshell

electrons with same value of n and l

orbital

electrons with same value of n, l and ml (2 per orbital)

isotope

equal number of protons, different number of neutrons= different mass number

2p orbital lobes/nodal planes

two lobes and one nodal plane

3d orbital lobes/nodal planes

four lobes and two nodal planes

Aufbau principle

electrons occupy the lowest-energy orbitals first

Pauli exclusion principle

each orbital can accommodate two electrons with opposite spins

Hund’s rule

most stable electron arrangement within orbital level has the greatest number of parallel spins

mass of atomic particles in order

electron < proton < neutron

Chromium special case

4s1,3d5

Copper special case

4s1,3d10

ionisation energy

energy required to remove an electron from a gaseous atom to form a positive ion