Now notice that in our group we have at least one of each. We have at least one nonmetal, at least one metalloid and at least one metal. Now every single element within this group can form four Covalent bonds with other nonmetals. And every atom except the sea atom, except our carbon can form two more additional bonds with lowest bases. Now remember what a lewis bases. It's simply an atom or a molecule that has an extra lone pair of electrons that it can donate to some other lewis acid.