Answer: Hydrogen and Helium
Explanation: Hydrogen is made from from one proton and one electron, making them one of the simplest forms of elements in the universe. Combining hydrogen atoms creates helium, the second most common element in the Universe.
Answer:
i think the first one is gravity and second one is rotation
Explanation:
Possibly electron shells, t<span>he </span>electrons<span> in the outermost occupied </span>shell<span> (or </span>shells<span>) determine the chemical properties of the atom..</span>
