Question

at seven features Time/ Period

Answer 1

Answer:

First period contains 2 elements 1H and 2 He and it is the shortest period.Second and third periods contain 8 elements each namely 3 Li to 10Ne and 10 Na to 18Ar and is a short period.Fourth and fifth period contains 18 elements each namely 19K to 36Kr and 37Rb to 54Xe and is a long period.Sixth period contains 32 elements namely 55Cs to 86Rn and is the longest period.Seventh period is incomplete. It has all other elements starting with 87Fr onwards.Elements from 93 onwards are purely synthetic and are called trans–uranium elements and is incomplete period.