4 atoms of Oxygen are required to make 2 atoms of hydrogen. The compound H2O is 1 Hydrogen and 2 Oxygen.
Answer:
<h3>homeostasis</h3>
•the maintenance of a stable internal environment
<u><em>Hope </em><em>this</em><em> helps</em><em> </em><em>:</em><em>)</em></u>
You haven't attached any options but anyways, to help you with your question, elements belonging to the same group (e.g. alkali metals, noble gases) all have the same chemical properties. Hydrogen, for example, have the same properties with Sodium, Potassium and Lithium.