Elements P, Q, R and S have atomic numbers 11, 15, 17 and 18 respectively. Which of them are reactive non-metals?

(a) P and Q

(b) P and R

(c) Q and R

(d) R and S

 

Answer

The electronic configurations of P, Q, R and S are as follows:

P(11): 2, 8, 1

Q(15): 2, 8, 5

R(17): 2, 8, 7

S(18): 2, 8, 8

Metals lose electrons to attain stability whereas non-metals gain electrons for the same.

METALS LOSE ELECTRONS TO ATTAIN STABILITY AND NON-METALS GAIN ELECTRONS - Teachoo.png

Now, checking the options:

  • Element P donates 1 electron to attain stability. Hence, it is a metal.
  • Element Q accepts 3 electrons to attain stability. Hence it is a non-metal.
  • Element R accepts 2 electrons to attain stability. Hence it is a non-metal.
  • Element S cannot accept anymore electrons. Hence, it is a noble-gas.

Since Q and R have a high tendency to accept electrons in order to attain noble gas configuration, they are reactive non-metals.

Therefore, the correct option is (c) Q and R

 

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo