I think the number of protons in the nucleus the number of valence electrons atomic mass...
The reason why the reaction written on the picture can be classified as a synthesis reaction is :
the reaction shows one compound that formed from two compounds
hope this helps
Water!!! (H2O) ........... :)
Atoms. Well, they can be broken down, but that won't happen that fast.
In general the inter- molecular attraction between particles of gases is much more smaller than those found in the particles of liquids. Because of this, the particles of gases are usually far apart from one another while the particles of liquid are closer together compares to that of gases.
