Explain why helium’s first ionisation energy is much higher than hydrogen’s.
Explain why lithium has lower ionisation energy than helium even though lithium has 1 proton more.
Why does the main trend of first ionisation energy increase across a period?
Explain why the ionisation energy of aluminium is lower than that of magnesium.
Explain why the first ionisation of magnesium is 736 kJ mol-1 whilst that of beryllium is 900 kJ mol-1.
Explain why the second ionisation energy of sodium is much higher than the second ionisation energy of magnesium.
The four successive ionisation energies of beryllium are: 900 1760 1480 21000 (kJ mol-1). Explain why there is a very big increase in ionisation energies between the second and third ionisation energies.
Give the group number for the following elements having these successive first ionisation energies.
799 2420 3660 25040 32850
1000 2260 3390 4540 6990 8790 27100 31700
736 1450 3740 7740 10500 1800 21700 25600
Which would have a greater value for the second ionisation energy: magnesium or aluminium?
Which would have a greater value for the third ionisation energy: magnesium or aluminium?