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Finding the formula between nitrogen and beryllium?

So what would be the appropriate formula when nitrogen reacts with beryllium?

I know that nitrogen is in group 5 so therefore has 5 valence electrons in it's outer shell. Similarly beryllium is in group 2 so has 2 valence electrons in it's outer shell.

What steps would I need to take to find the formula when the two elements react with each other?

I'm confused? Any help would be appreciated! Thanks!
We don't often consider beryllium compounds or nitrides so this looks difficult on the surface.
But it is just an ionic compound so we need to consider the ions formed by each element, and then work out their ratio in the product.

Beryllium is a group 2 metal so loses 2 electrons to form Be2+ ion.
Nitrogen has 5 outer shell electrons so will gain 3 electrons to form a nitride ion N3- . (Nitrogen can form other ions such but nitride is the most common / stable. Additionally you wouldn't be expected to be able to predict the formula of other nitrogen ions)

Therefore the formula of the compound beryllium nitride is Be3N2.
Reply 2
Original post by ChemistryWebsite
We don't often consider beryllium compounds or nitrides so this looks difficult on the surface.
But it is just an ionic compound so we need to consider the ions formed by each element, and then work out their ratio in the product.

Beryllium is a group 2 metal so loses 2 electrons to form Be2+ ion.
Nitrogen has 5 outer shell electrons so will gain 3 electrons to form a nitride ion N3- . (Nitrogen can form other ions such but nitride is the most common / stable. Additionally you wouldn't be expected to be able to predict the formula of other nitrogen ions)

Therefore the formula of the compound beryllium nitride is Be3N2.

Understood. So the key part to take in here is that when dealing with ionic compounds, it is possible to predict the ions that they make by adding more or taking away electrons until the ion has a full octet in place. Where taking away electrons makes the ion positive and vice versa.
Reply 3
Original post by ChemistryWebsite
We don't often consider beryllium compounds or nitrides so this looks difficult on the surface.
But it is just an ionic compound so we need to consider the ions formed by each element, and then work out their ratio in the product.

Beryllium is a group 2 metal so loses 2 electrons to form Be2+ ion.
Nitrogen has 5 outer shell electrons so will gain 3 electrons to form a nitride ion N3- . (Nitrogen can form other ions such but nitride is the most common / stable. Additionally you wouldn't be expected to be able to predict the formula of other nitrogen ions)

Therefore the formula of the compound beryllium nitride is Be3N2.

If you don't mind me asking, what approach would we take if we aren't dealing with an ionic compound i.e. something like phosphorus reacting with chlorine?
Original post by Yatayyat
Understood. So the key part to take in here is that when dealing with ionic compounds, it is possible to predict the ions that they make by adding more or taking away electrons until the ion has a full octet in place. Where taking away electrons makes the ion positive and vice versa.

Yes, although transition elements (and lanthanides and actinides) are not easy to predict in this way!

The method predicts the most likely ion, but others are also possible. For example nitrogen can also form the azide ion N3- but you wouldn't predict this in a simple question as it is not llikely to be formed under 'normal' conditions.
Original post by Yatayyat
If you don't mind me asking, what approach would we take if we aren't dealing with an ionic compound i.e. something like phosphorus reacting with chlorine?

For a covalent compound you need to know the oxidation state of each element.
Reply 6
Original post by ChemistryWebsite
Yes, although transition elements (and lanthanides and actinides) are not easy to predict in this way!

The method predicts the most likely ion, but others are also possible. For example nitrogen can also form the azide ion N3- but you wouldn't predict this in a simple question as it is not llikely to be formed under 'normal' conditions.

Okay I see why there would be no way of predicting the other ions and this wouldn't be expected. I can see why it would be right to consider the ions as these would be the most stable and common ions used.
Original post by ChemistryWebsite
For a covalent compound you need to know the oxidation state of each element.

Yes I agree. I have checked and have seen P to have oxidation state of +3 along with each chlorine atom to have a oxidation state of -1, so the compound would be PCl3 in order to give an neutral oxidation number.

Thanks alot for your help! :smile:
(edited 5 years ago)
Original post by Yatayyat
Okay I see why there would be no way of predicting the other ions and this wouldn't be expected. I can see why it would be right to consider the ions as these would be the most stable and common ions used.

Yes I agree. I have checked and have seen P to have oxidation state of +3 along with each chlorine atom to have a oxidation state of -1, so the compound would be PCl3 in order to give an neutral oxidation number.

Thanks alot for your help! :smile:

No problem

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