What happened when citric acid and and bicarbonate soda mixed together

The reaction follows the normal rules for an acid-carbonate reaction, which in turn is a special kind of acid-base reaction.

Acid + Carbonate -> Salt + Water + CO2

(Citric Acid) + (bicarbonate soda) -> (Trisodium citrate) + water + CO2

This is a very fast reaction, which produces a lot of carbon dixoide in a very short amount of time, which is the bubbles that you see. The other chemicals produce are clear liquids, so you don't see any of them.

The water cycle increase the water content in the earth atmosphere

In any atom of any element, you will find protons and neutrons in the nucleus of any atom