The number of elements present in $2^{\mathrm{nd}}, 3^{\mathrm{rd}}, 4^{\mathrm{th}}, 5^{\mathrm{th}}$ periods of modern periodic table respectively are

: Modern periodic table contains 7 periods. 

2 nd period → short period → it has eight elements → 2s&3p

3 rd period → short period → it has eight elements → 3s& 3p 

4 th period → long period → it has eighteen elements → 4s,3d, 4p 

5 th period → long period → it has eighteen elements → 5s, 4d,5p