Which of the following elements will sulfur most readily react with in order to help it fill its outer shell with 8 electrons? arsenic (As)
astatine (At)
argon (Ar)
magnesium (Mg)

Magnesium

Explanation:

Using the KLMN styled electronic configuration, the electronic configuration of sulphur with atomic number 16 is 2, 8,6

What this means is that it needs extra 2 electrons to fill into its M shell to attain the octet configuration.

Now let’s look at Magnesium, with atomic number 12, the electronic configuration it has is 2,8,2.

This means it has 2 extra electrons to give away so as to attain its own stability.

The sulphur atom will gladly accept the two electrons which the magnesium atom wants to give away. This makes it the perfect element to be reacted with sulphur to make it attain its octet configuration

the answer is barium and copper bromide