Atoms X and Y form an ionic compound with formula XY_2.
Which option below could give the correct atomic numbers for X and Y?
A. X = 11; Y = 16
B. X = 3; Y = 17
C. X = 12; Y = 9
D. X = 6; Y = 16
E. X = 14; Y = 8
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When looking at XY_2, we can conclude that for this compound to form, X must have double the valency of Y. This is why it would take two atoms of Y to react with one atom of X.
Let’s look at the electron configuration of each option:
For A,
X= 2,8,1 and Y= 2,8,6
This would take two atoms of X to react with one atom of Y, which is incorrect.
For B,
X= 2,1 and Y= 2,8,7
This would take one atom of X to react with one atom of Y, which is incorrect.
For C,
X= 2,8,2 and Y= 2,7
This would take two atoms of Y reacting with one atom of X, which is correct and our answer.
For D,
X= 2,4 and Y= 2,8,6
These atoms will share electrons, which is incorrect.
For E,
X= 2,8,4 and Y=2,6
These atoms will share electrons, which is incorrect.
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