Chemistry is a branch of science that involves the study of the composition, structure and properties of matter. Often known as the central science, it is a creative discipline chiefly concerned with ...

Computational chemistry describes the use of computer modelling and simulation – including ab initio approaches based on quantum chemistry, and empirical approaches – to study the structures and ...

For example, the atomic number of sodium is 11. Every sodium atom has 11 protons and 11 electrons. It has 11 positive charges and 11 negative charges. The mass number of an atom is its total number of ...