Atomic number should be the answer
Mass number = protons + neutrons = 34+46 =80
the element with an atomic number of 34 and mass number of 80 is selenium
Methane.
Water - H2O
Methane - CH4
Methane has 2 more hydrogens than water.
Uranium provides nuclear fuel used generate electricity in nuclear power station,also used by the military to power nuclear submarines and in nuclear weapons.