What makes the atom of one element different from another element’s atom?
A.Number of protons
B.Number of electrons
C.Number of neutrons
D.Number of ions

Hint: Chemical elements are the purest form of atoms. Only one type of atom is present. Each atom has three subatomic particles in it. There are a total of \[118\] elements in the periodic table. These all elements have different atomic numbers. Thus, atoms of one element are different from another by atomic number.

Complete answer:
Periodic table is the representation of chemical elements arranged in the increasing order of atomic number. There are a total of \[118\] elements in the periodic table. Elements are the purest form of atom. Thus, every element has a single type of atom in it. Each atom consists of a nucleus, a heavy portion present in the central portion of an atom. Inside the nucleus every atom consists of neutrons and protons.
The number of protons gives the atomic number. We know that every chemical element has its own atomic number. Thus, the atom of one element differs from another element’s atom by the number of protons.

Option A is the correct one.

Note:
Due to the presence of protons, the nucleus is positively charged. Outside the nucleus, electrons will be present. There will be an equal number of protons and electrons in every atom. The positive charge in the nucleus and the negative charge outside the nucleus are equal and opposite leads to the stability of the atom.