Which one of the following will have the largest number of atoms ?(i)  1 g Au (s)     (ii)  1 g Na (s)      (iii)  1 g Li (s)   (iv)  1 g of Cl2(g)

To determine which of the given substances has the largest number of atoms, we need to calculate the number of atoms in 1 gram of each substance. We can do this by using Avogadro's number (6.022 x 10^23 atoms/mole) and the molar mass of each substance.

Step 1: Calculate the number of moles in 1 gram of each substance.

(i) Au (Gold): The molar mass of Au is 197.0 g/mole. So, the number of moles in 1 g of Au is 1/197.0 = 0.00508 moles.

(ii) Na (Sodium): The molar mass of Na is 23.0 g/mole. So, the number of moles in 1 g of Na is 1/23.0 = 0.04348 moles.

(iii) Li (Lithium): The molar mass of Li is 6.94 g/mole. So, the number of moles in 1 g of Li is 1/6.94 = 0.14409 moles.

(iv) Cl2 (Chlorine gas): The molar mass of Cl2 is 70.9 g/mole. So, the number of moles in 1 g of Cl2 is 1/70.9 = 0.01410 moles.

Step 2: Calculate the number of atoms in each substance.

(i) Au: 0.00508 moles x (6.022 x 10^23 atoms/mole) = 3.06 x 10^21 atoms

(ii) Na: 0.04348 moles x (6.022 x 10^23 atoms/mole) = 2.62 x 10^22 atoms

(iii) Li: 0.14409 moles x (6.022 x 10^23 atoms/mole) = 8.67 x 10^22 atoms

(iv) Cl2: 0.01410 moles x (6.022 x 10^23 atoms/mole) = 8.49 x 10^21 atoms

From these calculations, we can see that 1 g of Li (Lithium) has the largest number of atoms.