What is the correct name for the ionic compound MgI_2?

• A. Magnesium(II) iodide
• B. Magnesium iodide
• C. Magnesium diiodide
• D. Magnesium iodine

Answer: (B)

Verified step by step guidance

1. Identify the cation and anion in the compound MgI_2. Magnesium (Mg) is the cation and iodide (I^-) is the anion.
2. Determine the charge of the magnesium ion. Magnesium typically forms a +2 charge, written as Mg^{2+}.
3. Determine the charge of the iodide ion. Iodide is a halide ion with a -1 charge, written as I^-.
4. Balance the charges to form a neutral compound. Since magnesium has a +2 charge and iodide has a -1 charge, two iodide ions are needed to balance one magnesium ion, giving the formula MgI_2.
5. Name the compound by stating the cation name first (magnesium) followed by the anion name with the suffix '-ide' (iodide). Since magnesium has only one common charge, no Roman numeral is needed, so the correct name is 'magnesium iodide'.