Define:

(a) Symbol

(b) Molecular formula

(c) Radical

(d) Valency

(a) A symbol is the short hand representation for the atom of a specific element. Each chemical element has its own unique symbol. For example, H represents Hydrogen, and O represents Oxygen.

(b) A molecular formula of a compound is the symbolic representation of its one molecule which shows the number of atoms of each element present in it.

(c) Radical is an atom of an element or a group of atoms of the same or different elements that behave as a single unit and has positive or negative charge.

(d) Valency is the combining capacity of an atom of an element or of a radical with the atoms of other elements or radicals to form molecules.