Mg--->Mg-2 +2e,I don't understand why it isn't -2e since Mg ion would lose 2e--->atom

Mg--->Mg-2 + 2e, I don't understand why it isn't -2e since Mg ion would lose 2 electrons to become an atom?

In my head, this makes sense to me........Mg--->Mg-2 - 2e

please help me understand, thank you

Reply 1

BJack

19

Magnesium becomes Mg²⁺, not Mg^2-.

Reply 2

Cinamon

15

Mg--->Mg-2 +2e is wrong

It would be:

Mg + 2e- ---> Mg2-

or

Mg --> Mg2+ + 2e-

Reply 3

VaVe

8

Think of it like this:
Mg -2e -> Mg2+

Then just move the electrons to the other side and you have
Mg -> Mg2+ + 2e. It's saying when you form a magnesium ion you also get 2 electrons
reactant -> product

(edited 13 years ago)

Reply 4

Schemilix

11

'Lose two electrons to become at atom'?

I think you're more confused than you think. As the above poster said, plus a charged particle is called an ion.

Reply 5

A level Az

16

It's a balanced equation, so both sides have to be equal in charge.

Mg -----> Mg^2+ + 2e^-

0 (aka no charge) -----> 2+ charge + 2- charge

0 = 2-2

0 = 0

That's how you write it. It's positive (not negative as you've wrote it) because it has lost electrons. Positive means the atom lost electrons, negative means the atom gained electrons.

Reply 6

BuuTuu

OP

7

ohhhh, ok I get it now, thank youuu everyone :smile:

Reply 7

studychill7

1

Original post by Cinamon

Mg--->Mg-2 +2e is wrong

It would be:

Mg + 2e- ---> Mg2-

or

Mg --> Mg2+ + 2e-

Will it be wrong if i write Mg - 2e- ---> Mg2+ ?

Reply 8

TypicalNerd

18

Original post by studychill7

Will it be wrong if i write Mg - 2e- ---> Mg2+ ?

This is an 11-year old thread…

Some exam boards (OCR mainly) do allow that, but you are definitely better off writing

Mg —> Mg^2+ + 2e^-

Reply 9

Navier203aonosm

1

Original post by VaVe

Think of it like this:
Mg -2e -> Mg2+

Then just move the electrons to the other side and you have
Mg -> Mg2+ + 2e. It's saying when you form a magnesium ion you also get 2 electrons
reactant -> product

I don't quite understand why you have to move it over to the right side? Is there a specific reason for not being able to write it as 'Mg-2e=Mg2+', while 'O+2e=O2-' can be written this way? Is the negative sign too unsightly?

Mg--->Mg-2 +2e,I don't understand why it isn't -2e since Mg ion would lose 2e--->atom

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