1) Calculate the molar weight. 12.000 + 4*(35.45)
2) Divide 15.0 by the molar weight to get moles
3) Multiply by Avogado's number of get the number of molecules.
If the refrigerator has no room to cool the meat that you've just cooked, then you should clear it with other stuff or food that has not been consumed for days. There might be some goods that are not good for consumption anymore even though it has been placed in the ref for a couple of days. Hope this answers your question.
Answer:
Hydrogen
Explanation:
Hydrogen has only 1 proton and has an atomic mass of 1. It does not have neutrons. Helium and above have higher mass than Hydrogen.