how many atoms of Na are there in every 2.5g of Na? please answer me! thank you!

Answer 1

You need to calculate how many moles of Na you have and then use that each mole of any substance contains 6.02 x 10^23 particles (in this case atoms).

So number of moles of Na is
2.5 g /23 g mole^-1

hence calculate the number of atoms knowing that each mole contains
6.02x10^23 atoms.