The atomic number of an element is simply the number of protons in the center of its atoms.

This number is very important because it tells us what the element is.

For example:

• Hydrogen has an atomic number of 1, which means it has 1 proton.
• Carbon has an atomic number of 6, so it has 6 protons.
• Oxygen has an atomic number of 8, meaning it has 8 protons.

Knowing the atomic number is super important because:

1. Elements with the same atomic number are the same and act in similar ways in chemical reactions.
2. The atomic number helps us know where the element goes on the periodic table.

In short, the atomic number helps us understand what an element is, how it is built, and how it behaves.