Question

Which of the following electron configurations in the outermost shell is characteristic of alkali metals?
A.$(n - 1){s^2}{p^6}n{s^2}{p^1}$
B.$(n - 1){s^2}{p^6}{d^{10}}n{s^1}$
C.$(n - 1){s^2}{p^6}n{s^1}$
D.$n{s^2}n{p^6}(n - 1){d^{10}}$

Answer 1

In the given question it is asked about the electronic configuration of the given s-block elements. Now to find it we just have to mention the number we obtain regarding the subshells at the end of the configuration like in this case the number of the electrons in each kind of subshell would give the answer as $(n - 1){s^2}{p^6}{d^{10}}n{s^1}$

Complete step by step solution:
In the given question we have to find out the option among the given which rightly demonstrates the general electronic configuration by the alkali metals.
Now first we should be aware of the alkali metals. They are:
The first group elements of the periodic table apart from the Hydrogen which persists ambiguous properties for the case of any one group.
Now these are the group of atoms with most reactive metallic tendencies among their respective periods.
There are mainly 6 of them in the chemistry found yet, they are lithium, sodium, potassium, rubidium, caesium, and francium.
Now to find the correct general electronic configuration regarding the given set of elements we have to mention them step by step :
Step 1: first of all we need to have a variable value as $n$ which denotes the period to which the element belongs. Now specifically for the case of the d-block this value of $n$ would vary between $2 - 7$.
Step 2: we have to provide the ultimate configuration by giving the denotations of s, p and d subshells in the terms of the $n$ and number of electrons in each subshell.
For the case of the first s subshell the number of the shell would be $n - 1$ and the number of electrons would be $2$, so that would give us a resemblance of $(n - 1){s^2}$.
For the case of p subshell the number of the shell would be $n - 1$ and the number of electrons would be $6$, so that would give us a resemblance of $(n - 1){p^6}$.
For the case of the first s subshell the number of the shell would be $n - 1$ and the number of electrons would be $10$, so that would give us a resemblance of $(n - 1){d^{10}}$.
For the case of s subshell the number of the shell would be $n$ whereas we know that the number of electrons would be $1$, so that would give us a resemblance of $n{s^1}$.
Therefore that would make the final answer as the $(n - 1){s^2}{p^6}{d^{10}}n{s^1}$.
So the correct option would be option $(n - 1){s^2}{p^6}{d^{10}}n{s^1}$.

Hence, the correct answer is option B.

Note: Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.