• qais
  • Content Quality

This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Electronic configuration of A,B and c
A, 12 = 2,8,2
B,18 =2,8,8
C,20= 2,8,8,2
Hence, looking at the electronic configuration, A and C have same valency and valence electron, so they both will show similar properties.
According to me
atomic number 12=magnesium
atomic number 20 =calcium
these both lie in same table (alkaline earth metals )
so these two elements show similar properties
I am still 5 th class
plz mark as brailest pleaseeeeeeeeeeee pleaseeeeeeeeeeee