8. in what family would each of these elements be classified?
radium -
tin -
iodine -
cesium -

 Radium is a member of the alkaline metals group.

Tin is classified in the 'Other Metals' section which can be located in groups 13, 14, and 15 of the Periodic Table.

Iodine is classified as a halogen — a subset of very chemically reactive elements (Group 17 on the periodic table) that exist in the environment as compounds rather than as pure elements. The other halogens include fluorine (F), chlorine (Cl), bromine (Br) and astatine (At).

Cesium is classified as an "Alkali Metal" and located in Group 1 elements of the Periodic Table. An Element classified as an Alkali Metal is a very reactive metal that does not occur freely in nature. Alkali metals are soft, malleable, ductile, and are good conductors of heat and electricity.

a and c

c is 100% but i am confused in a

where are the vectors ?