6: Electron configuration

How many electrons can fill the first shell?

Two

How many electrons can fill the second shell?

Eight

How many electrons can fill the third shell?

18

how many electrons can fill the fourth shell?

32

What is an atomic orbital?

Region around the nucleus that can hold up to 2 electrons with opposite spins

What happens as the shell number increases?

Energy increases

Shells are regarded as what?

Energy levels

What is the principal quantum number n?

The shell or energy level number

How many electrons can an orbital hold?

1 or 2

What is the shape of a S orbital

Spherical

The radius of an S orbital increases as?

Shell number increases

What is the shape of a p-orbital?

Dumbbell

Each shelf from N=1 contains how many S orbitals?

1

Shell from N = 2 contains how many P orbitals?

3

Each shell from N = 3 contains how many D orbitals?

5

Shell from N = 4 contains how many F orbitals?

7

what is a sub shell?

A group of orbitals of the same type within a shell

The sub shell 4s fills before which sub-shell? why?

3d 3d is at a higher energy level.

Why do two electrons in an orbital have to have opposite spins?

To counteract the repulsion between the two negative charges on the two electrons

How are orbitals filled up?

Singly before pairing up

Why are chromium and copper exceptions to some of the rules?

A 3d sub shell is more stable when either half or completely full

Copper: 1s2 2s2 2p6 3s2 3p6 3d5 4s1

Chromium: 1s2 2s2 2p6 3s2 3p6 3d10 4s1

Isoelectronic

The same number of valance electrons, but different number of protons (different species)

As n increases what happens to the energy gap?

The gap between successive shells get smaller so orbital in neighbouring shells may overlap