Q 2P - Chemistry: Molecular Nature Of Matter And Change

Question

Question: Write the general electron configuration of a transition element

 (a) In Period 5;

 (b) In Period 6.

Step-by-Step Solution

Answer

1. The electron configuration in general is:    $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}4{\mathrm{p}}^{6}5{\mathrm{s}}^{2}4{\mathrm{d}}^x$
2. The arrangement is:   $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}4{\mathrm{p}}^{6}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^{6}6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^{\mathrm{x}}$        

Step 1: Define General electron configuration

The arrangement of orbital energy levels for s, p, d, and f-block elements of the periodic table is known as the general electron configuration or electronic structure of atoms or ions.

Step 2: For the general electron configuration of a transition element

All transition elements in Period 5 have the same "base" configuration of$\left[\mathrm{Kr}\right]5{\mathrm{s}}^2$, but the quantity of  d electrons $\left(\mathrm{x}\right)$ in that configuration varies.

As a result, the electron configuration in general is: 

$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}4{\mathrm{p}}^{6}5{\mathrm{s}}^{2}4{\mathrm{d}}^x$

Step 3: Finding for period six

The f sublevel electrons are lower in energy than the d sublevel electrons in a generic electron configuration for Period 6 transition elements.

As a result, the arrangement is$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}4{\mathrm{p}}^{6}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^{6}6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^{\mathrm{x}}$