2 hydrogen atoms hope this helps
Reaction of calcium with water
Calcium reacts slowly with water. This is in contrast with magnesium, immediately above calcium in the periodic table, which is virtually unreactive with cold water. The reaction forms calcium hydroxide, Ca(OH)2 and hydrogen gas (H2).
1. From grams -> mole:
=grams given x 1 mol/molar mass
So 150 g Cu x 1 mol Cu/63.546 g Cu = 2.4 mol Cu
2. From mole -> atoms
=number of mol x 6.022x10^22 atoms/1 mol
So 2.4 mol Cu x 6.022x10^22 atoms Cu/1 mol Cu = 1.4 x 10^24 atoms Cu
