Home PYQs UPPSC UPPSC MCQs Prelims 2003 (GS Paper I)

Question

Isotopes are atoms of an element whose:

  1. atomic weight is same, but atomic number is different
  2. atomic weight different, but atomic number same
  3. atomic number and atomic weight are same
  4. none of these

Answer:

Option B: atomic weight different, but atomic number same

Detailed Solution:

The correct answer is “atomic weight different, but atomic number same”.

Isotopes are known as the atoms of the same element having the same atomic number i.e same number of protons, but different atomic mass numbers i.e different numbers of neutrons.