Periodic Trends

Question 1

Atomic radius:

Answer 1

Refers to the distance between an atoms valence shell and its nucleus.
- Increases down a group
- Decreases from left to right of a period (greater positive nuclear charge)

Question 2

First ionisation energy:

Answer 2

Measures the minimum energy required to remove the single loosely bound electron from its atom.
- Decreases down a group (further away from nucleas, so less positive nuclear charge acting on the shell, therefore less energy required to remove it).
- Increases from left to right (electron shielding effect, more electrons subsidises the effect of positive nuclear charge, because of like charge repulsion.)

Question 3

Electronegativity:

Answer 3

The ability for an atom to gain an electron.
- increases from left to right (more positive nuclear charge)
- Decreases down a group.