Help with Identifying the group in ionic compund formulas

[NickP717]

Homework Statement

Identify the group to which X belongs in each ionic compound formula. Enter your response using the group number.

a) MgX
b)XCl2
c) XF2

Homework Equations

The Attempt at a Solution

The first one I figured out was group 16. However, the next two I thought were group 1, but I keep getting the wrong answer. Help anyone?

 

[Borek]

What must be X valence?

 

[chemisttree]

Homework Statement

Identify the group to which X belongs in each ionic compound formula. Enter your response using the group number.

a) MgX
b)XCl2
c) XF2

Homework Equations

The Attempt at a Solution

The first one I figured out was group 16. However, the next two I thought were group 1, but I keep getting the wrong answer. Help anyone?

Its got to balance two negative charges so...