Lithium Iodide is
LiI
Lithium has a charge of 1+, and Iodide has a charge of 1-, thus this is the correct form.
Remember Iodine is Diatomic when it is alone! So I_2
LiI (s) -> Li (s) + I_2 (g)
Is the formula you get when you simply write it out, but now we need to balance it.
1 Lithium, 1 Iodide -> 1 Lithium + 2 Iodine
We need 2 Iodine on the left side, so we can add coefficients to the left to create that balance.
2(1 Lithium, 1 Iodide) -> 1 Lithium + 2 Iodine
is the same as...
2LiI -> Li + I_2
Now we have to balance the Lithiums on the right.... so our final balanced equation is:
2LiI -> 2Li + I_2
(Note that the _2 is a subscript of 2)
