91Ó°ÊÓ

The given data can be listed below as,

· The mass of one mole of nickel is, 59g or 0.059 kg.

· The density of nickel is, $\mathrm{ÒÏ}=8.8g/c{m}^3$orrole="math" localid="1668551564749" $\mathrm{ÒÏ}=8.8×{10}^{3}kg/m^3$

The quantity of particles in one mole of a substance is known as Avogadro's number. It can be used to change moles into particles or particles into particles.

According to the question,

1 mole of nickel = Avogadro atoms = 0.059kg

$1m^3$of nickel = $\mathrm{ÒÏ}kg$

$$\begin{gathered} \mathrm{ÒÏ}kg=\frac{\mathrm{ÒÏ}}{0.059moles} \\ =Avogadro×\frac{\mathrm{ÒÏ}}{0.059atoms} \end{gathered}$$

The mobile electron density is expressed as,

$$\begin{gathered} =\frac{\mathrm{ÒÏ}}{0.059moles} \\ =Avagadro×\frac{\mathrm{ÒÏ}}{0.059atoms} \end{gathered}$$

Substitute all the value in the above equation

The mobile electron density is,

$$\begin{gathered} =6.023×{10}^{23}×\frac{8.8×{10}^{3}kg/m^3}{0.059} \\ =8.98×{10}^{28}kg/m^3 \end{gathered}$$

Hence the mobile electron density is,$8.98×{10}^{28}kg/m^3$