Topic 1 - Atomic Structure and the Periodic Table

Question 1

What is an isotope?

Answer 1

One of two or more forms of the same element that contain equal numbers of protons, but differ in number of neutrons.

Question 2

Why is there a decrease in ionisation energy down the groups?

Answer 2

Shielding increases, as the number of electron shells increases, and therefore the energy needed to remove an electron from orbit is lower.

Question 3

Why is there an increase in ionisation energy across the periods?

Answer 3

The increasing nuclear charge, without any major increase in shielding increases the attractive force of the nucleus on the electrons.