Modern Basis of Classification of Elements: Knowledge of the structure of the atom led to the discovery of a new property of the elements called the atomic number. The atomic number of an element is equal to the number of protons in its atom. It is also equal to the number of electrons present in the neutral atom. No two elements can have the same value as an atomic number. The isotopes of an element have the same atomic number but different atomic weights. Because of the same atomic number, they possess similar chemical properties. These facts indicate that the … Continue reading Modern Basis of Classification of Elements- Modern Periodic Law