Quantum mechanical model

Question 1

orbits vs. orbitals

Answer 1

Orbits :
Bohr model
Two dimensional
Distance from nucleus is fixed
Path is elliptical or circular

Orbitals: density plots showing rpobability of finding an electron
Quantum model
Three dimensional (x,y,z planes)
Distance from nucleus varies
No set path

Question 2

quantum mechanics

Answer 2

application of quantum theory to explain the properties of matter, particularly electrons in atoms

Question 3

wave function

Answer 3

the mathematical probability of finding an electron in a certain region of space

Question 4

electron probability density

Answer 4

probability of finding an electron at a given location, derived from wave equations and used to determine the shapes of orbitals also called an electron probability distribution

Question 5

quantum numbers

Answer 5

describe the quantum mechanical properties of orbitals; from the solutions of Schrodinger’s wave equations
- required to describe any distinct electrical charge of the electron creates in its own magnetic feild

• there are 4 quantum numbers

Question 6

principal quantum number

Answer 6

• shells
• the quantum number that describes size and energy of an atomic orbital, whole number values, the higher the shell number the further it is from the nucleus
• (n) #1-7

Question 7

the secondary quantum number

Answer 7

• subshells
• describes shape, a positive number from 0– n-1
  -(l)
  0=s
  1=p
  2=d
  3=f

Question 8

the magnetic quantum number

Answer 8

• (ml)
• describes orientation of an atomic orbital in space relative to other orbitals in the atom
• has to be whole number values equal or less then l
• can only be -l or +l

Question 9

the magnetic spin quantum number

Answer 9

• relates to the spin of the electron
• limitied to either +1/2 or -1/2
• since only 2 e- are able to fit in any one orbital, the e- accquire a positive (upright) or negative (downward) spin
• electrons behave as tiny magnets, they spin about its axis, the revolving electrical charge of the electron creates its own magnetic feild

Question 10

formula for total # of orbitals for any energy level

Answer 10

n^2

Question 11

the formula for the greatest # of electrons possible for any energy level

Answer 11

2n^2

Question 12

the afbau principle

Answer 12

electrons enter lowest avalible energy level first

Question 13

pauli’s exclusion principle

Answer 13

• no 2 e- in the same atom can have the sane 4 quantum numbers
• 2 electrons can go in each orbital, providing they have opposite spins

Question 14

hund’s rule of maximum multiplicity

Answer 14

• when in orbitals of equal energy, electrons will try to remain unpaired
• all in row must have one e- before another is added

Question 15

exceptions to the 3 electron configuration laws

Answer 15

cu, ag, au- all fill in 3d orbital before 4s to create more stable, also explains why cu can be cu+ and cu2+

• cr and mo, to acheive a more stable arrangement of lower energy, one of the 43 electrons is promoted into the 3d oribital to give 6 unpaired electrons with lower repulsion (w does not do this due to sheidlijg affect from f orbital)

Question 16

more stable meaning

Answer 16

maximizes attractive forces and minimizes repulsive forces

Question 17

why is iron magnetic

Answer 17

• the more unpaired e-, the more magnetic
• iron exhibits magnetic properties because it has 4 unpaired e- in its d orbota; that all have the same directionbal spin and all act as small magnets
• multiple iron atoms that have the same unpaired e- orientated in the same direction generate stronger magnetic feild

Question 18

how is the periodic table arranged

Answer 18

according to the way electrons arrange themselves around the nuclei of atoms