At stp, an element that is a brittle solid and a poor conductor of heat and electricity could have an atomic number of
(1) 12 (3) 16
(2) 13 (4) 17

Option (2) is the correct answer.

Explanation:

It is known that non-metals do not conduct electricity.

Carbon has atomic number 12, sulfur has atomic number 16, and chlorine has an atomic number 17. All these elements are non-metals.

Whereas aluminium has atomic number 13 and it is a poor metal.

So, aluminium being a poor metal is a brittle solid and a poor conductor of heat and electricity.

i'm assuming that the correct answer is indeed the first one/ "a"..

the answer is 0.8m.

by: nicholas