What is the net charge on a magnesium ion after losing two electrons?

[Jess_18033152]

Homework Statement

Calculate the net charge on a magnesium ion which has lost two electrons.

2. The attempt at a solution
I put 2+ as my answer and this is what I was told, but I don't understand what they mean by the following;

That's a chemist's shorthand, not the amount of charge on the ion.
You did not give the correct unit.
Does the magnesium ion gain or lose charge when it loses electrons?
Be careful with the number of electrons lost!
The question asks for the charge, which should be given in SI units.

 

[kuruman]

1. Often 2+ is shorthand notation for the amount of charge on an ion. You were expected to provide a full answer.
2. The full answer must show a number and the appropriate units. The symbol "+" is not an appropriate unit.
3. This comment does not make much sense to me. The question clearly states that the ion has lost electrons and since electrons carry charge, then the ion has lost charge.
4. I think this means that you didn't correctly translate the loss of two electrons to the creation of net charge on the ion.
5. This comment reinforces comment 2 in that the appropriate units must be SI units.

In summary, the instructor who provided these comments appears not to be convinced that you understand how the loss of two electrons in the ion can be translated into a number of SI charge units including the appropriate sign. The correct answer was expected to have the format
After the loss of two electrons, the net charge on the ion is _____ (+ or -) __________ (number other than 2) ________ (SI units).
Can you fill in the blanks?