chemistry electrons and ionisation energy

what is the maximum number of electrons in each of the first 4 shells

1-2

2-8

3-18

4-32

what is the formula for working out the maximum number of electrons in a shell

2n²

orbital definition

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

what is an orbital

a region in space where there is a high probability of finding an electron

what are the different types of orbitals

s,p,d,f

what is the shape of an s orbital

sphere

what is the shape of a p orbital

dumbbell

what is a sub-shell

orbitals of the same type grouped together

how many electrons can each type of orbital hold (maximum)

s-2

p-6

d-10

f-14

what is the model used to show electrons with spins in orbitals

‘electrons in box’

what is the order of sub-shells in an electron configuration (36 electrons)

1s 2s 2p 3s 3p 4s 3d 4p

why does the 4s sun-shell fill up before the 3d sub-shell

has a lower energy level and sub-shells are filled from the lowest energy

ionisation energy definition

the energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

factors affecting ionisation energy

atomic radius

nuclear charge

electron shielding

how does atomic radius affect ionisation energy

greater distance between nucleus and outermost electron = less nuclear attraction= easier to loose an electron = lower ionisation energy

how does electron shielding affect ionisation energy

less electron shielding = greater nuclear attraction

how does nuclear charge affect ionisation energy

greater nuclear charge= greater nuclear attraction = greater ionisation energy

trend in first IE down a group

1st IE decreases down a group as atomic radius increases and electron shielding increases, decreasing the nuclear attraction

trend in 1st IE across a period

1st IE increases across a period as nuclear charge increases and atomic radius decreases resulting in a lower nuclear charge