According to valence bond theory, which kind of orbitals overlap to form the p−cl bonds in pcl5?

orbital.

Explanation:

Valence bond theory is the chemical bonding theory which explains the chemical bond between two atoms. Both of the two atoms shares each of the unpaired electron to form a hybrid orbital and together to form a bond.

According to the valence bond theory, P-Cl bond forms by the overlap of a phosphorus orbital with chlorine 3p orbital to form five sigma bond (P-Cl). The five orbital are single occupied. has a trigonal bipyramidal structure, and the bond angle is 90 and 120 degree. The original atomic orbital are no longer exist.

c. orbital shape i hope this is correct

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.