Question

1. Identify isotopes and isobars:
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Answer 1

Answer :-

$\bull \: \: \: \: \: \: \: \: \sf{{}^{40}_{20}X} \: \: and \: \: {}^{40}_{18}X \: \: are \: \: \bf{isobars}$

$\bull \: \: \: \: \: \: \: \: \sf{{}^{40}_{20}X} \: \: and \: \: {}^{39}_{20}X \: \: are \: \: \bf{isotopes}$

Explanation :-

$\bull \: \: \: \: \: \: \: \: \sf{{}^{40}_{20}X} \: \: and \: \: {}^{40}_{18}X \: \: are \: \: \bf{isobars}$

Reason: Isobars are the atoms of different elements having different atomic number but same mass number. So, $\sf{{}^{40}_{20}X} \: \: and \: \: {}^{40}_{18}X$ are isobars.

Here,

$\sf{{}^{40}_{20}X}$ has,

• Atomic number = 20
• Mass number = 40

And,

$\sf{{}^{40}_{18}X}$ has,

• Atomic number = 18
• Mass number = 40

Hence, they are having same atomic number. So, it is an isobar.

$\bull \: \: \: \: \: \: \: \: \sf{{}^{40}_{20}X} \: \: and \: \: {}^{39}_{20}X \: \: are \: \: \bf{isotopes}$

Reason: Isotopes are the atoms of same element having same atomic number but different mass number. Hence, $\sf{{}^{40}_{20}X} \: \: and \: \: {}^{39}_{20}X$ are isotopes.

Here,

$\sf{{}^{40}_{20}X}$ has,

• Atomic number = 20
• Mass number = 40

And,

$\sf{{}^{39}_{20}X}$ has,

• Atomic number = 20
• Mass number = 39

Hence, they are having same atomic number. So, it is a isotope.