Question

An element with atomic number 3 combines with another element with atomic number 17. What would be the formula of the compound?​

Answer 1

Answer:

Atomic no. 3 element is Lithium (Li).

Atomic no. 17 element is Chlorine (Cl).

Valency of Li is 1.

Valency of Cl is 1.

So formula obtained is LiCl .

Answer 2

Answer:

formula will be LiCl

Explanation:

Li-lithium , atomic number 3 , electronic configuration - 2 , 1 and orbital - 1s2 2s2 , valency 1 , i.e. it has to donate 1 electron to be stable  and  Cl-chlorine , atomic number 17 , electronic configuration - 2,8,7 and orbital 1s2 , 2s2 2p6 , 3s2 , 3p6 ,  valency 1 , i.e. it needs to accept an electron to be stable .. so lithium will donate its 1 electron to chlorine and both the elements will be stable .. formula--- lithium - valency 1 , Chlorine - valency 1  hence valency 1 and 1 will cancel out and formula will be LiCl