Question

Elements X, Y and Z have atomic numbers 6, 9 and 12 respectively. Which one forms anions, form cations and have 4 electrons in their outermost shell.

Answer 1

Here, X has atomic number 6 so it's electronic configuration is 2, 4 .
Y with atomic number 9 has electronic configuration 2,7.
Z atomic number 12 has electronic configuration 2,8,2.

So, here Y is anion with valency -1.
Z is cation with valency +2.
X has 4 valence electrons.