Now for more Google which says the atomic mass of iron is 55 g (ie. 1 mole of iron atoms weigh 55g), oxygen is 16g, silicon is 28g and magnesium 24g.
Do you know what a mole is I wonder – it’s just a definition of a weighable amount of atoms. 1 mole of atoms is 6×10^23 atoms.
2×10^24 kg of iron, or 4×10^25 moles (mass/mass of a mole) or 2×10^49 atoms of iron
2×10^24 kg of oxygen, or 1×10^26 moles, or 6×10^49 atoms of oxygen
1×10^24 kg of silicon, or 2×10^49 atoms
1×10^24 kg of magnesium, or 2×10^49 atoms.
Add it together and it’s 1×10^50 atoms by my estimate. That’s