Question

1. magnesium chloride has the chemical formula mgcl₂

what does the subscript 2 indicate?
has two magnesium and two chloride atoms.
there are two magnesium ions for every chloride ion.
there are two chloride ions for every magnesium ion.
there are two magnesium atoms in total.
clear all

Explanation:

In the chemical formula \( \text{MgCl}_2 \), the subscript 2 is associated with chlorine (Cl). Magnesium (Mg) has a +2 charge, and chloride (Cl⁻) has a -1 charge. To balance the charges, one \( \text{Mg}^{2+} \) ion combines with two \( \text{Cl}^- \) ions. So the subscript 2 indicates there are two chloride ions for every magnesium ion. Let's analyze the other options:

• The first option is wrong because the formula has 1 Mg and 2 Cl atoms per formula unit, not two of each.
• The second option is wrong as the ratio is 1 Mg to 2 Cl, not 2 Mg to 1 Cl.
• The fourth option is wrong because the subscript on Mg is 1 (implied), so there's one Mg atom per formula unit, not two.

Answer:

There are two chloride ions for every magnesium ion.