1. Determine the number of valence electrons:
* Magnesium (Mg) has 2 valence electrons.
* Bromine (Br) has 7 valence electrons.
2. Arrange the atoms:
* Magnesium (Mg) is in Group 2, so it typically forms a +2 cation (Mg²⁺).
* Bromine (Br) is in Group 17, so it typically forms a -1 anion (Br⁻).
* To balance the charges, we need two bromine atoms (2Br⁻).
3. Draw the Lewis structure:
* Magnesium loses its two valence electrons, forming a Mg²⁺ ion with no dots around it.
* Each bromine atom gains one electron, forming Br⁻ ions with 8 dots around them.
Here's the Lewis structure:
```
[ Mg ]²⁺ [ :Br: ]⁻ [ :Br: ]⁻
```
Key Points:
* The brackets indicate the ions.
* The charges are shown outside the brackets.
* Each bromine atom has a complete octet (8 electrons).
* Magnesium has no valence electrons left.
Important Note: This Lewis structure represents the ionic bond between magnesium and bromine. It's important to remember that ionic compounds don't exist as single molecules, but rather as a lattice structure with alternating ions.
