Answer:
Sodium, carbon, hydrogen, oxygen
Step-by-step explanation:
Sodium citrate is a compound which is also known by a name 'trisodium citrate'. It is a derivative of citric acid with sodium cation instead of all three acidic protons in the acid. Citric acid is a carboxylic acid, meaning it consists of carbon, hydrogen and oxygen atoms. The only difference in sodium citrate is that it has acidic protons replaced with sodium cations.
This generally would be the most logical approach to the question if we actually didn't know the molecular formula. However, molecular formula proves that our logic was correct, as it is:
To summarize, we have sodium, carbon, hydrogen and oxygen atoms present in sodium citrate.