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# Chemistry : Compound watch

1. Magnesium produces a 2+ ion and oxygen produces a 2- ion. Explain how you would calculate the formula for the compound magnesium oxide using this information.
2. Essencially because magnesium is a 2+ ion and oxygen is a 2-. The common denominator of this is 2. What do you multiply by 2 to get 2? 1 so it is a 1:1 ratio and would be MgO.

For something harder such as iron (III) and oxygen to make iron oxide,
Iron has. 3+ charge and oxygen has a 2- charge. The common denominator of these numbers is 6.
For iron, what do you multiply 3 by to get 6? = 2. So it would be Fe(subscript 2)
For oxygen, what do you multiply 2 by to get 6? = 3. So it would be O(subscript 3)
So overall it would be Fe2O3.
It’s all about balancing the charges
3. (Original post by 12doeb)
Essencially because magnesium is a 2+ ion and oxygen is a 2-. The common denominator of this is 2. What do you multiply by 2 to get 2? 1 so it is a 1:1 ratio and would be MgO.

For something harder such as iron (III) and oxygen to make iron oxide,
Iron has. 3+ charge and oxygen has a 2- charge. The common denominator of these numbers is 6.
For iron, what do you multiply 3 by to get 6? = 2. So it would be Fe(subscript 2)
For oxygen, what do you multiply 2 by to get 6? = 3. So it would be O(subscript 3)
So overall it would be Fe2O3.
It’s all about balancing the charges
Oh I get it now thank you very much.

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Updated: March 14, 2018
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