Answer:
a) bromine , mercury .
b) Oganesson .
c) Group 4A (or IVA) of the periodic table includes the nonmetal carbon (C), the metalloids silicon (Si) and germanium (Ge), the metals tin (Sn) and lead (Pb), and the yet-unnamed artificially-produced element ununquadium (Uuq).
d)thorium (Th), protactinium (Pa), uranium (U).