How to calculate the maximum charge of an atom or a molecule

[HCverma]

Homework Statement

How to calculate the maximum charge of an atom or a molecule?
As we know the equivalent weight = atomic weight / maximum charge
Al, Ca and O2

The Attempt at a Solution

Al, E = 27/3 = 9
Ca, E = 40/2 = 20
O2, E = 16/2 = 8
I see on the books that the charges of Al, Ca and O2 are 3, 2 and 2 but
How to find the charges of Al, Ca and O2?

 

[Borek]

the maximum charge of an atom or a molecule?

And how is it defined?

 

[lomidrevo]

And how is it defined?

Good question... I would say that atom has the maximum possible charge when it is fully ionized, but I have the feeling this is not the real goal of the problem...

 

[HCverma]

And how is it defined?

Could you please tell me how to see my old threads?

 

[Borek]

Hoover the mouse over MY PF (upper toolbar), click "Your profile page" in the menu, look in the "recent activity" or "postings" tab.

 

[epenguin]

I agree with 2 and 3. Definitions are important, but I recommend to not be hung up on them to the point of losing sight of acquiring essential ordinary ideas of chemistry.

Your numbers given by a division are something or other different from charges, probably to do with (related. concept of) equivalent masses (confusion?).

When an atom or molecule is charged it is usually not called atom or molecule any more but 'ion'.
Atoms or molecules may commonly lose or acquire electrons in their 'outer shells' mostly when they are surrounded by other stuff to and from which it is easy for them to lose or acquire them, expecially in aqueous solution or in crystals. The number lost or gained, and hence the charge acquired is easily calculated from knowledge of an element's position in the periodic table, or atomic number. At least this is true more often than not, the cases you first meet. E.g in solution, you get Al³⁺, Ca²⁺. Then for important heavier elements it's more complicated but not very, and rationalisable.

(Not in ordinary chemistry but in mass spectrometry, which us a somewhat specialised technique but which all chemists must know about, atoms and molecules are given a single charge (mostly) by electron bombardment etc.)

More than this not really profitable now IMO, you probably need to plough ahead in your general textbook without stopping here!

 

[Nik_2213]

Probably not what you intended, but accelerators and various astrophysical processes may strip atoms to their bare nuclei.