I want to know how do you writte oxygent, nitrogent, and hydrogen in chemical equation?

Do you mean oxygen and nitrogen?

Because oxygent is a synthetic blood hospitals use to keep donor organs in. Please check your meaning of the message before you press submit.

If your asking how to write Oxygen, Nitrogen and Hydrogen in a chemical equation it is

O for oxygen
N for nitrogen
H for hydrogen

Right, the symbols for the elements oxygen, nitrogen and hydrogen are O, N and H respectively.

But if you want the formula of the molecules of oxygen, nitrogen and hydrogen, then they are: O_2,\ N_2\ and\ H_2 respectively.