Element A has 3 electrons in the outermost orbit and element B has 6 electrons in the outermost orbit. The formula of the compound formed A and B would be?

  1. #A_2B_3#
  2. #A_2B_6#
  3. #A_2B#
  4. #A_3B_2#

1 Answer
Nov 24, 2017
  1. #A_2B_3#

Explanation:

Similar to your other posted question. I do hope that you UNDERSTAND the application instead of just copying answers.

In a neutral (uncharged) molecule, the sum of the bonding valence electrons must be equal. So, the products of the negative element and its charge and the positive element and its charge must be equal.
#C_1 xx N_1 = C_2 xx N_2#

If we have a 3 valence electrons, the "A" charge will be either +3 or -5 for a full octet, and 6 valence electrons in "B" atoms will most likely result in acquisition of additional electrons (2) for an octet and relative charge of -2. Thus, "A" will be the positive ion, at +3.
Balancing the two:
#3 xx A = -2 xx B#

To be equal, #A = 2# and #B = 3#

#A_2B_3#