Question

There are three elements A, B and C with atomic number 2,10,5. Among these which belongs to same period?​

Answer 1

atomic number 2 =Helium

atomic number 10=Neon

atomic number 5=Boron

Here boron and neon belongs to same period and helium and neon belongs to same group

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Answer 2

Explanation:

atomic number 5 is Boron (B) and atomic number 10 is Neon(N),they both lie in same period but different group