Atoms of two different elements must have different electrical charges numbers of neutrons atomic numbers energy levels

## Step 1<br />Atoms of two different elements must have different atomic numbers. This is because the atomic number of an element is determined by the number of protons in its nucleus. <br /><br />## Step 2<br />Each element has a unique number of protons, which distinguishes it from other elements. For example, hydrogen has 1 proton, helium has 2, and so on. <br /><br />## Step 3<br />Therefore, atoms of two different elements must have different atomic numbers.