Adopting the number of avogrado 6.02 10²³ / mol
Nickel Molar Mass = 58.7 g / mol
We will first have to find the number of moles in 2.12 grams of the element, like this:
1 mol ----------------- 58.7 g
X ---------------------- 2.12 g
58.7 x = 2.12 1
58.7x = 2.12
\(x = \frac{2.12}{58.7}\)
X ≈ 0.036 mol
Now we will find how many atoms there are in 0.036 mol of this element, like this:
1 mol -------------------- 6.02 10²³ atoms
0.036 mols ----------------- X
X = 0.036 6.02 10²³
X ≈ 0.21 * 10²³ atoms
or
\(\boxed{\boxed{x \approx 2.1 * 10^{24}\:atoms}}\end{array}}\qquad\quad\checkmark\)
