Question

what does the line mean The atom of one element are different from the atom of all other elements?​

Answer 1

Answer:

Each element has its own characteristic atomic number. Atoms of the same element can have different numbers of neutrons, however. Atoms of the same element (i.e., atoms with the same number of protons) with different numbers of neutrons are called isotopes.

Normally, the number of electrons is equal to the number of protons, which makes atoms electrically neutral. The number of protons in an atom is the defining feature of an atom. It's what makes one element different from another. The number of protons in an atom is called its atomic number.