The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Why does solid Phosphorus have 4 atoms?

I'm currently doing some chemistry questions (page 18 of OCR AS & Year 1 textbook).

This is the question:

Write a balanced with state symbols for the following reaction:

Magnesium reacts with solid phosphorus to form solid magnesium phosphide.

The answer, according to the back of the book says:

6Mg + P⁴ → 2Mg³P²


My question is how can you know or work out that solid Phosphorus in the product has four atoms? Same goes the Mg and the P in the result have their respective 3 and 2 atoms (all before balancing out the equation).
Original post by Grashex
I'm currently doing some chemistry questions (page 18 of OCR AS & Year 1 textbook).

This is the question:

Write a balanced with state symbols for the following reaction:

Magnesium reacts with solid phosphorus to form solid magnesium phosphide.

The answer, according to the back of the book says:

6Mg + P⁴ → 2Mg³P²


My question is how can you know or work out that solid Phosphorus in the product has four atoms? Same goes the Mg and the P in the result have their respective 3 and 2 atoms (all before balancing out the equation).


It's just something that you have to learn...

Phosphorus exists as simple P4 pyramidal molecules, sulfur as S8 crown shaped molecules.

P4.gif
Attachment not found
S8.gif12.9KB

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you