Explanation:
The chemical formula magnesium sulfide written as MgS and NOT 
because charge on magnesium ion is +2 and charge on sulfide ion is -2.
Therefore, these charges will cancel out each other as we write the formula in simplest crisscross method.
Also, the numbers in a chemical formula display the total number of atoms attached with each other or central atom.
For example, in 
there are two chlorine atoms attached to one calcium atom.
Therefore, 
denotes one sulfur atom is attached to magnesium atom. Hence, we do not write the formula of magnesium sulfide as because this shows two magnesium atoms are attached to two sulfur atoms which is not true.
In 3.8 moles of li, there are about <span>0.144071459 grams. I assume that you are talking about lithium.</span>
I think the correct answer is the first option. It has nonpolar bonds and a symmetrical structure. The structure of a BF3 molecule shows a symmetrical trigonal geometry. The net dipole moment of the molecule is zero therefore it is polar.
If you change the subscripts it would change the reactants or products and then you would be solving a different formula, you would change what the chemical is
