[bmack]

I am trying to write out the name and formula for different compounds.

For example Calcium Oxide is Ca O.

How do I decipher when it should end it " ide" and not " ate"?  I was told that if there are two that the the more metallic element comes first followed by the less metallic...then that is " ide" and s compound ending in " ate" contains Oxygen and two or more elements...huh I am not processing this info  correctly because I thought oxide should end with " ate"

Then there is MgS  I wrote this out as magnesium sulfide ?! Is this correct?


Please help I would truly appreciate it.

[Yggdrasil]

In ionic compounds you will have a cation and an anion.  For the cations, if the cation is a single atom (e.g. Ca²⁺, Na⁺, Al³⁺) then the cation will just be the name of the atom.  A polyatomic cation (e.g. NH₄⁺) will have a "-ium" ending (e.g. ammonium, guanidinium, hydronium, etc.).

For anions there is a similar scheme.  Anions which consist of a single atom will have an "-ide" ending (e.g. S^2- = sulfide, Cl^- = chloride).  Polyatomic atoms will generally have an "-ate" ending (e.g. SO₄^2- = sulfate, CH₃COO^- = acetate) although there are special rules for naming oxyanions.

[bmack]

 I truly appreciate your help. However I am almost certain that you confused me more.  I really do not understand

I think I get it! NO3 is Nitrate because there are 3 oxygens in the compound, and so it should end in "ate"

I know I am hella slow...sorry but I truly appreciate your help I really, really do.

[Yggdrasil]

There really isn't a good way to explain how the number of oxygens determines the suffix on your anion's name.  Nitrate (NO₃^2-) has three oxygens as does chlorate (ClO₃^-) but both phosphate (PO₄^3-) and sulfate (SO₄^2-) have four oxygens.

The best answer I can tell you is that you have to memorize the names polyatomic anions which end in -ate.  Unfortunately, there is no systematic relationship between number of oxygens in the anion and its name.  However, once you know that chlorate is ClO₃^-, you can find the structures of chlorite, hypochlorite, and perchlorate by following the rules outlined in the wikipedia page I posted earlier.

[bmack]

My initial question was how to determine what ends in "ide" and what ends in "ate". So the reason that chlorate (ClO3-) , phosphate (PO43-) and sulfate (SO42-)  end in " ate" is because they contain oxygen right!

two or more elements that contain oxygen end in "ate" I just need to know if this is correct? I think I am on the right path however, I may not be asking the question correctly.


I am not saying that the number of oxygens determine the suffix, I am saying the fact that the compound includes oxygen is the reason it ends in "ate" ...isnt that true. It seems that it is. I just want to confirm.

[Yggdrasil]

In that case yes.  Anions which end in -ide contain only one atom (sulfide = S^2-, chloride = Cl^-).  Anions which end in -ate, have oxygen (sulfate = SO₄^2-, chlorate = ClO₃^-).

[Borek]

Anions which end in -ide contain only one atom (sulfide = S^2-, chloride = Cl^-)

With some exceptions unfortunately. Like cyanide...