Answer:
5.75x10^22 atoms
Explanation:
From a clear understanding of Avogadro's hypothesis, we discovered that 1mole of any substance contains 6.02x10^23 atoms. This implies that 1mole of Al also contains 6.02x10^23 atoms.
1mole of Al = 27g
If 27g of Al contains 6.02x10^23 atoms, then 2.58g of Al will contain = (2.58 x 6.02x10^23)/27 = 5.75x10^22 atoms