Explain the trend of first ionisation energy down a group.

The first ionisation energy is the energy required to remove one electron from an atom. Down a group, there are more electron shells surrounding the nucleus, which results in a greater shielding from the nuclear charge on the outermost electron shells. This makes it easier to remove an electron, as there is a weaker nuclear attraction, so a lower energy is required to overcome it. This is why the first ionisation energy decreases down a group.

RW

Related Chemistry A Level answers

All answers ▸

Why do first ionisation energies decrease down a group but increase across a period?


Describe the mechanism for bromination across a double bond


Describe, in three steps, how you would synthesise phenylethylamine (C6H5CH2CH2NH2) from methylbenzene, giving reagents and conditions for each step. For each step, state the type of reaction that occurs.


A solution of ethanoic acid is made by dissolving 3g of pure liquid propanoic acid in 500cm^3 water. Given the pH of the solution is 2.98, calculate Ka.