Me with this chemistry question, image attached.

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

Which type of reaction always has an element and a compound as reactants

What kind of ion is contained in salts that produce an acidic solution? a positive ion that attracts a proton from water a positive ion that releases a proton to water a negative ion that attracts a proton from water a negative ion that releases a proton to water