The number of aluminium ions present in 54 g of aluminium (atomic weight 27) is

To find the number of aluminium ions (atoms) in 54 g of aluminium, we first calculate the number of moles. The number of moles is determined by dividing the given mass by the atomic weight. Given a mass of 54 g and an atomic weight of 27, the calculation is 54 g / 27 g/mol, which equals 2.0 moles. According to Avogadro's principle, one mole of any substance contains approximately 6.022!5 10^23 particles. Therefore, the total number of aluminium ions is calculated by multiplying the number of moles by Avogadro's number: 2.0 moles!5 6.022!5 10^23 ions/mole. This results in approximately 1.2044!5 10^24 ions, which corresponds to option 4.