Atomic Number - GCSE Physics Definition

The atomic number is a fundamental property of an element and is defined as the number of protons found in the nucleus of an atom. It is the defining feature that determines the identity of an element, as each element on the periodic table has a unique atomic number.

For example;

• The atomic number of hydrogen is 1 meaning it has 1 proton in its nucleus

• The atomic number of carbon is 6 meaning it has 6 protons in its nucleus

The atomic number not only helps in identifying an element but also determines the element's position in the periodic table, and it is fundamental in understanding chemical behaviour and bonding.

In a neutral atom, the atomic number is also equal to the number of electrons, which balance the positive charge of the protons. Understanding atomic numbers is essential for students studying GCSE Physics, as it lays the foundation for exploring the structure and properties of matter.