What is the name of the compound with the formula MgI2
The Correct Answer and Explanation is:
The name of the compound with the formula MgI₂ is magnesium iodide.
Explanation:
Magnesium iodide is an ionic compound formed from a metal and a non-metal. To name it correctly, we follow the standard rules for naming binary ionic compounds.
- Identify the cation and anion:
- The formula MgI₂ shows that the metal magnesium (Mg) combines with iodine (I).
- Magnesium is a metal found in Group 2 of the periodic table, meaning it typically forms a 2+ charge (Mg²⁺).
- Iodine is a halogen found in Group 17. When it becomes an ion, it gains one electron and becomes an iodide ion (I⁻) with a 1− charge.
- Determine the ratio of ions:
- Since each magnesium ion has a 2+ charge, it takes two iodide ions (each with a 1− charge) to balance out one magnesium ion.
- This is why the chemical formula is MgI₂. It shows one Mg²⁺ ion and two I⁻ ions.
- Naming the compound:
- In ionic compounds, the metal (cation) name comes first and remains unchanged.
- The non-metal (anion) name is modified to end in “-ide”.
- Therefore, Mg becomes magnesium, and I (iodine) becomes iodide.
- The final name is magnesium iodide.
- No prefixes are needed:
- In ionic compounds, we do not use prefixes like “di-” or “tri-” in the name, even if there are multiple anions.
- The charges determine the ratio, and that is shown in the formula, not in the name.
In conclusion, MgI₂ is correctly named magnesium iodide, and it consists of magnesium cations and iodide anions in a 1 to 2 ratio, forming a neutral ionic compound.
