Question

Which of the following sets of elements do not belong to the same group?

• A. $F,Cl,Br$
• B. $Na,K,Rb$
• C. $P,S,Cl$
• D. $C,Si,Ge$

Answer 1

The correct option is C $P,S,Cl$

All the elements in a particular group have the same number of valence electrons and hence possess similar chemical properties. Among the given options:

a) $F,Cl,Br$ are classified as halogens and have 7 valence electrons. Thus they belong to group 17 of the periodic table.

b) $Na,K,Rb$ are classified as alkali metals and have 1 valence electron. These elements are present in group 1 of the periodic table.

c) Phosphorus has 5 valence electrons and belongs to group 15.
Sulphur has 6 valence electrons and belongs to group 16.
Chlorine has 7 valence electrons and thus belongs to group 17 in the modern periodic table.

d) $C,Si,Ge$ belong to the carbon family and have 4 valence electrons, and they are present in group 14 of the periodic table.