Group 14

Carbon and Silicon are non-metals, Germanium a metalloid and lead a metal. The metallic character down a group is associated with:

1. Lower ionization energy, making them more willing to form cations and lose electrons into a "sea".
2. More diffuse shells, meaning less directional bonding.

Carbon and silicon have a high affinity for hard anions such as O^2- and F^-. The heavier group 14 elements such as lead prefer soft anions such as I^- and S^2-. Hardness refers to small radii, high oxidation states and low polarizability.

All group 14 elements form tetravalent hydrides (EH₄, catenation (bonds between the same element) decreases down the group. This is associated with decreasing E-E bond entropy.

The largest silane (Si_nH_n+2 chain that can form is heptasilane. Silicon's larger number of electrons means more intermolecular force. So while propane is a gas at room temperature  trisilane boils at 53 degrees.

Something called the inert-pair effect increases down the group, which results in a tendency to form +2 rather then +4.