Which atom of water is associated with the cation? which atom of water is associated with the cation? oxygen atom, because the partial negative charge is localized on the oxygen atom. hydrogen atom. since the number of hydrogen atoms is twice the number of oxygen atoms, it is more probable for the cation to be associated with the hydrogen atom.

Oxygen atom, because the partial negative charge is localized on the oxygen atom.

Explanation:

A cation is a positive ion, so to associate with it, would be necessary a negative ion, an anion. When the water dissociates, it will form and .

So, oxygen has a negative charge, and in the molecule, the partial negative charge because it's more electronegative. Then, oxygen will be associated with the cation.

protons have a positive charge