The hydronium ion, often represented as H3O+, carries a positive charge. This ion forms when a water molecule (H2O) gains an additional hydrogen ion (H+). The extra hydrogen ion attaches itself to one of the lone pairs of electrons on the oxygen atom in the water molecule, resulting in a positively charged ion.
In simpler terms, the hydronium ion has a charge of +1. This is because it has one more proton (from the additional hydrogen ion) than it has electrons, making it positively charged.
Understanding the charge on the hydronium ion is crucial in chemistry, especially when dealing with acids and bases. The presence of hydronium ions in a solution is what makes it acidic.