Which amongst the following has more number of atoms?
(i) 11.5 g of sodium, or
(ii) 15 g of calcium [Na = 23, Ca = 40]

Explanation

To solve the problem of determining which substance has more atoms between 11.5 g of sodium and 15 g of calcium, we need to calculate the number of moles of each substance and then convert that to the number of atoms. Here’s a step-by-step solution:

### Step 1: Calculate the number of moles of sodium (Na)
The formula to calculate the number of moles is:
\[ \text{Number of moles} = \frac{\text{mass of substance (g)}}{\text{molar mass (g/mol)}} \]
For sodium:
...