Q 15P - Chemistry: Molecular Nature Of Matter And Change

Question

Question: Give the electron configuration and the number of unpaired

electrons for: $\left(a\right)\mathbf{ }{\mathbf{Cr}}^{\mathbf{+}\mathbf{3}}\mathbf{ }\left(b\right)\mathbf{ }{\mathbf{Ti}}^{\mathbf{+}\mathbf{4}}\mathbf{ }\left(c\right)\mathbf{ }{\mathbf{Co}}^{\mathbf{+}\mathbf{3}}\mathbf{ }\left(d\right)\mathbf{ }{\mathbf{Ta}}^{\mathbf{+}\mathbf{2}}$

Step-by-Step Solution

Answer

1.   $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^1$with $1$unpaired electron.
2.   $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^6$with $0$ unpaired electrons.
3.   $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{1}3{\mathrm{d}}^5$with $6$ unpaired electrons.
4.   $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^{6}6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^1$with $1$ unpaired electron. 

Step 1: Electron Configuration and Unpaired electrons.

• The distribution of electrons in atomic or molecular orbitals of an atom, molecule, or other physical structure is known as electron configuration. 
• An unpaired electron could be a single electron that occupies an atom's orbital instead of as a part of a pair. Each of an atom's atomic orbitals (defined by the three quantum numbers n, l, and m) can hold two electrons (electron pair) with opposite spins.

Step 2: Electron Configuration and Unpaired electrons of Given Elements

(a) Based on the periodic table, Cr has the atomic number of $24$, therefore it has $24$ electrons. Electronic configuration is: $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^5$.

When it gains a charge of $+3$, it loses $3$ electrons, and will have only $21$  electrons with electron configuration:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^1$ with$1$unpaired electron.

 

(b) Based on the periodic table, Ti has the atomic number of $22$, therefore it has $22$electrons. Electronic configuration is:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^2$.

When it gains a charge of $+4$, it loses $4$ electrons, and will have only $18$electrons with electron configuration:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^6$with $0$ unpaired electrons

 

(c) Based on the periodic table, Co has the atomic number of $27$, therefore it has $27$electrons. Electronic configuration is:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^7$.

When it gains a charge of $+3$, it loses $3$ electrons, and will have $24$electrons with electron configuration:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{1}3{\mathrm{d}}^5$ with $6$ unpaired electrons.

 

(d) Based on the periodic table, Ta has the atomic number of $73$, therefore it has $73$electrons. Electronic configuration is:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^{6}6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^3$.

When it gains a charge of $+2$, it loses $2$electrons, and will have only $71$ electrons with electron configuration:$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^{10}5{\mathrm{s}}^{2}4{\mathrm{d}}^{10}5{\mathrm{p}}^{6}6{\mathrm{s}}^{2}4{\mathrm{f}}^{14}5{\mathrm{d}}^1$.