Trends in the Periodic Table: ionisation energy, electronegativity, atomic radius, melting and boling poins

Ionisation energy is the energy to remove the first electron from an atom in the gaseous state.
- Increases across a period as electron shells go from near empty to full.
- Decreases down a group as the outer electrons become further removed from the positive nucleus.
- The second ionisation energy is always greater than the first since the electron is now being removed from a positive ion.
Electronegativity is the relative power to attract electrons.
- Increases across a period as the number of protons increases so does the positive charge of the nucleus, thus a stronger attraction and e…