Question

Write the density of Silver, Nickel, Lanthanum, Neptunium, Tin, and Protactinium and arrange them from the least dense to the densest.

Answer 1

Silver $\left(\mathrm{Ag}\right)$:

• It is a metal with the atomic number $47$ which belongs to the $\mathrm{d}-$ block.
• Silver is placed in the $4\mathrm{d}$ series and group $11$.
• The electronic configuration of silver can be written as $\left[\mathrm{Kr}\right]4{\mathrm{d}}^{10}5{\mathrm{s}}^1$ where $\left[\mathrm{Kr}\right]=$ the electronic configuration of the inert gas Krypton.

Nickel $\left(\mathrm{Ni}\right)$:

• It is a metal with the atomic number $28$ that belongs to the $\mathrm{d}-$block.
• Nickel is placed in the $3\mathrm{d}$ series and group $10$.
• The electronic configuration of nickel can be written as $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{8}4{\mathrm{s}}^2$ where $\left[\mathrm{Ar}\right]=$ the electronic configuration of the inert gas Argon.

Lanthanum $\left(\mathrm{La}\right)$:

• It is metal with the atomic number $57$ and belongs to the inner transition elements.
• It is the first element of the $4\mathrm{f}$ block series.
• The electronic configuration of Lanthanum can be written as $\left[\mathrm{Xe}\right]4{\mathrm{f}}^{0}5{\mathrm{d}}^{1}6{\mathrm{s}}^2$ where $\left[\mathrm{Ar}\right]=$the electronic configuration of the inert gas Xenon.

Neptunium $\left(\mathrm{Np}\right)$:

• It is a synthetic metal produced by the transformation of the naturally occurring elements by nuclear reactions.
• It belongs to the $5\mathrm{f}$ block (actinoid series) series of the inner transition elements.
• The electronic configuration of Neptunium can be written as $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{4}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$, where $\left[\mathrm{Rn}\right]=$ the electronic configuration of the inert gas Radon.

Tin $\left(\mathrm{Sn}\right)$:

• Tin is metal with the atomic number $50$ belongs to the $\mathrm{p}-$ block.
• It belongs to the Carbon family (group 14) placed in period 5.
• The electronic configuration of Tin can be written as $\left[\mathrm{Kr}\right]4{\mathrm{d}}^{10}5{\mathrm{s}}^{2}5{\mathrm{p}}^2$, where $\left[\mathrm{Kr}\right]=$ the electronic configuration of the inert gas Krypton.

Protactinium $\left(\mathrm{Pa}\right)$:

• It is an inner transition element with atomic number $91$.
• It belongs to the $5\mathrm{f}$ block (actinoid series) series of the inner transition elements.
• The electronic configuration of Protactinium can be written as $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{2}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$ , where $\left[\mathrm{Rn}\right]=$the electronic configuration of the inert gas Radon.

Densities of the above elements:

• Silver- $10.9$ ${\mathrm{gcm}}^{-3}$
• Nickel- $8.9$ ${\mathrm{gcm}}^{-3}$
• Lanthanum- $6.5$ ${\mathrm{gcm}}^{-3}$
• Tin- $7.26$ ${\mathrm{gcm}}^{-3}$
• Neptunium- $20.2$ ${\mathrm{gcm}}^{-3}$
• Protactinium- $15.4$ ${\mathrm{gcm}}^{-3}$

Arrangement of the above elements in the increasing order of their densities:

• $$\begin{gathered} 6.5{\mathrm{gcm}}^{-3}<7.26{\mathrm{gcm}}^{-3}<8.9{\mathrm{gcm}}^{-3}<10.9{\mathrm{gcm}}^{-3}<15.4{\mathrm{gcm}}^{-3}<20.2{\mathrm{gcm}}^{-3} \\ \mathrm{Lanthanum}<\mathrm{Tin}<\mathrm{Nickel}<\mathrm{Silver}<\mathrm{Protactinium}<\mathrm{Neptunium}. \end{gathered}$$