Isotopes

• The sum of the protons and neutrons in an atom is its mass number.
• Atoms of the same element can have different numbers of neutrons; these atoms are called isotopes of that element.
• The sum of the protons and neutrons in an atom is its mass number.
• Atoms of the same element can have different numbers of neutrons but same number of protons ; these atoms are called isotopes of that element.