Following are some of the most important trends of a period table.
1. Atomic size –
The atomic size increases as one moves down the group and decreases on moving across the period from left to right.
2. Metallic character –
Metallic character increases as one moves down the group and decreases on moving from left to right in a PT.
3. Non metallic character –
The non metallic character increases on moving from left to right in a PT whereas it decreases on moving down the group.
4. Electron affinity –
It can be regarded as the energy released by an atom when an electron is added to it. It increases on moving from left to right whereas decreases from moving down the group.
exception – fluorine does not have the highest EA instead Chlorine does.
5. Ionization energy –
It is the minimum amount of energy required to remove an electron from the valence shell. On moving down the group, the ionization energy decreases while on moving across from left to right it increases.