number of atoms, physical science

How many Nitrogen?
How many Hydrogen?
How many Phosphorus?
How many Oxygen?
How many Strontium?
How many Phosphorus?
How many Oxygen?
How many Magnesium?
How many Oxygen?
How many Hydrogen?
How many Sulfur atoms in #2?
How many Oxygen atoms in #6?
How many Phosphorus atoms in #8?
How many Oxygen atoms in #9?
How many Phosphoris atoms in #15?
How many Hydrogen atoms in #18?