Science
Explain with examples
(i) Atomic number,
(ii) Mass number,
(iii) Isotopes and
(iv) Isobars.
Give any two uses of isotopes.
Answer
(i) Atomic number — The number of protons present in the nucleus of an atom is defined as the atomic number and is denoted by Z.
Example: Atomic number of hydrogen (Z) = 1 as only one proton is present in the nucleus of hydrogen atom.
(ii) Mass number — The total number of protons and neutrons present in the nucleus of an atom is known as the mass number and is denoted by A.
Example: Mass number of Carbon (A) = 12 as it has 6 protons and 6 neutrons.
(iii) Isotopes — The atoms of the same element having the same atomic number but different mass number are known as isotopes.
Example: Carbon has two isotopes 6C12 and 6C14
(iv) Isobars — Atoms of different elements with different atomic numbers, which have same mass number are known as isobars.
Example: Calcium [20Ca40] atomic number 20 and argon [18Ar40] atomic number 18 are isobars as both have same mass number i.e., 40 and different atomic numbers.
Isotopes have special properties which makes them useful in various fields like:
- An isotope of uranium is used as a fuel in nuclear reactors.
- An isotope of cobalt is used in the treatment of cancer.
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