Question

four elements P,Q,R and S belong to the 3rd period of modern periodic table and have respectively 1,3,5 and 7 electrons in their outermost shell1) Write the electronic configuration of Q and R and determine their valences? 2) Write the molecular formula of the compound formed when P and S combines

Answer 1

Q= 2,1 . R= 2,3 these are electronic configuration.

Answer 2

1) Electronic configuration of Q=2,8,3

Electronic configuration of R=2,8,5

2) Molecular formula of the compound when P and S combines:-

P=2,8,1 (metallic) and S=2,8,7 (non metallic)

Formula=P+S-