Prove from the following resutls that mercury molecules are monoatomic:
(a) 10g of mercury combine with 0.8g of oxygen to form an oxide.
(b) 1000mL of vapour of Hg at NTP weigh 8.923g
(c) The specific heat of the metal is 0.033.

Explanation

(a) Equivalent mass of Hg
`=("Mass of metal")/("Mass of oxygen")xx8=(10)/(0.8)xx8=100`
(b) Mass of 1000 mL of Hg vapour at NTP=8.923g
Mass of 22400mL of Hg vapour at NTP=`(8.923)/(1000)xx22400`
`=199.87g`
Hence: molecular mass of Hg `=188.87g`
(c) Approximate atomic mass `=(6.4)/("Sp.heat")=(6.4)/(0.033)=193.93g`
Valence of Hg `=(193.93)/(100)=2` (nearest whole number )
So, accurate atomic mass =Eq. mass `xx` Valence
`=100xx2=200g`
Automicity `=("Mol.mass")/("At.mass")=199.88)/(200)=1`
Hence, mercury molecules are monoatomic.