Question

Name the periods and groups to which the element with atomic number 15 belongs

Answer 1

fifth group,third period which is phosphorous

Answer 2

$your \: answer$
1) a group is determined by number of valence electrons

2) a period is determined by number of shells

given atomic number 15
configuration =2,8,5

it is containing 3 shells so period 3
and 5 valence electrons so 5 group

$hope \: helps$