Check sibling questions

An element ‘X’ belongs to 3rd period and group 16 of the Modern Periodic Table.

(a) Determine the number of valence electrons and the valency of ‘X’.

(b) Molecular formula of the compound when ‘X’ reacts with hydrogen and write its electron dot structure.

(c) Name the element ‘X’ and state whether it is metallic or non-metallic.



X belongs to the 3rd period. So, it has 3 shells.

X belongs to the 16th group.

Group number = 10 + number of valence electrons 

16 = 10 + number of valence electrons

Number of valence electrons = 16 - 10 = 6

Valency = 8 - 6 = 2


Number of valence electrons of X = 16 - 10 = 6

Valency of X = 8 - 6 = 2


X has a valency of 2 and Hydrogen has a valency of 1 so the formula of the compound formed by them will be H 2 X

Electron dot structure of H 2 X:  

Electron dot structure of H2X - Teachoo.png



The element X is sulphur.

  Metals lose electrons to become stable whereas, non-metals gain electrons to become stable.

Sulphur gains electrons to become stable. Hence it is a non-metal.

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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 13 years and a teacher from the past 17 years. He teaches Science, Economics, Accounting and English at Teachoo