Explain with examples
(i) Atomic number,
(ii) Mass number,
(iii) Isotopes and
(iv) Isobars.
Give any two uses of isotopes.
(i) Atomic number : The number of protons present in the nucleus of an atom is called atomic number. It is denoted by Z. e.g., in \(_{20}^{40}{Ca}\), atomic number = 20
(ii) Mass number : The sum of the number of protons and neutrons present in the nucleus of an atom is called mass number. It is denoted by A. e.g., in \(_{20}^{40}{Ca}\), mass number = 40
\(_{Z}^{A}{X}\) ← Element
(iii) Isotopes : The atoms of the same elements having same atomic number but different mass numbers are called isotopes, e.g., \(_{17}^{37}{Ca}\) and \(_{17}^{35}{Cl}\)
(iv) Isobars : The atoms of the different elements having same mass number but different atomic numbers are called isobars. e.g., \(_{20}^{40}{Ca}\) and \(_{18}^{40}{Ca}\)
Uses of isotopes :
- As nuclear fuel : An isotope of uranium (U – 235) is used as a nuclear fuel.
- In medical field : An isotope of cobalt is used in the treatment of cancer.