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 …

…in more tightly. - Increases down a group as the number of electron shells increase. Melting and Boiling Points - Increases to Group IV, then rapidly decreases. - Groups I and II (Metallic bond). Moderate to high - Group IV (Covalent network solids). Very high - Group VII (Diatomic covalent). Forces between molecules are weak so it's low. - Group VIII (Monatomic gases). Only forces between atoms are weak dispersion forces so its very low