Name the following molecules: (a) NF3 (b) SO3 (c) SiF4

This is a binary covalent compound. The first element is nitrogen, and the second is fluorine. There is one nitrogen atom and three fluorine atoms.
The name is Nitrogen trifluoride.

This is a binary covalent compound. The first element is sulfur, and the second is oxygen. There is one sulfur atom and three oxygen atoms.
The name is Sulfur trioxide.

This is a binary covalent compound. The first element is silicon, and the second is fluorine. There is one silicon atom and four fluorine atoms.
The name is Silicon tetrafluoride.

The names of the molecules are:

(a) NF$_{3}$: Nitrogen trifluoride

(b) SO$_{3}$: Sulfur trioxide

(c) SiF$_{4}$: Silicon tetrafluoride