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Question Question 6
Define the following terms:
(a) Atomic number
(b) Mass number
(c) Nucleons
(d) Valence shell
(a) The number of protons present in the nucleus of the atom of an element is called its atomic number.
(b) The sum of the number of protons and the number of neutrons present in the nucleus of the atom of an element is called the mass number of that element.
(c) The protons and neutrons are collectively called as nucleons.
(d) The outermost shell of an atom is known as its valence shell or valence orbit.