What is the empirical formula for a compound that contains 0.0134 g of iron, 0.00769 g of
sulfur and 0.0115 g of oxygen?

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom