Write application of isotopes .

Isotopes are the atoms of the same element with same atomic no: and different mass numbers. ... ⇒As isotope of uranium is used as a fuel in nuclear reactor. ⇒An isotope of iodine is used in the treatment of goitre. ⇒An isotope of cobalt is used in the treatment of cancer.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.