is the energy needed to remove 1 electron from an atom in 1 mole of gaseous atoms.
Nuclear charge - More protons = stronger attraction
Distance from nucleus - Fall off rapidly with distance, electron close will be stronger attached
High ionisation energy means theres a high attraction between electron and the nucleus
Ionisation energy decreases down group 2
- Extra electron shell
- Extra shielding
- Outer electrons are further away, nucleus attraction will be greatly reduces
Ionisation energy increases across a period
- Number of protons increase, stronger nuclear attraction
- Rougly same energy levels
- Little extra shielding
- The drop shows sub shells filling up, (moving from 's' to 'p')
Drop between 2 & 3 shows sub-shell structure.
Aluminiums outer electron is in a 3p orbital rather than 3s, slightly higher energy than 3s. Further from the nucleus.
Additional shielding from the 3s.
Drop between 5 & 6 is due to electron repulsion.
The shielding is identical but in phosphorus the electron is being removed from a singly-occupied orbital. In sulfur the electron is being removed from an orbital containing two electrons. The repulsion between 2 orbitals means that electrons are easier to remove.
Moles = Concentration * Volume (in cm3)
Ideal gas equation
pV = nRT
p = pressure (Pa)
V = volume (m2)
n = number of moles
R = 8.31 J K-1mol-1
T = Temperature (K)