Question

How do you write the noble-gas electron configuration for $B$ ?

Answer 1

The electronic configuration says about how the electrons are distributed in atomic orbitals. The electronic configuration is filled according to the energy they have. They follow the standard notion in which electrons containing the atomic subshells are placed in a sequence. For example, the Boron’s electronic configuration; $B\, = \,1{s^2}\,2{s^2}\,2{p^1}$ .

Complete step-by-step answer:
The boron is the fifth element in the periodic table. Its electronic configuration is as follows; $B\, = \,1{s^2}\,2{s^2}\,2{p^1}$

Whereas, in the condensed form of electronic configuration, the noble gas makes it easier to denote it.
So, let’s see how the noble gas configuration of boron will be; $B\, = \,\left[ {He} \right]\,2{s^2}\,2{p^1}$

Boron $(B)$ whose atomic number is $5$ , which is having $5$ electrons. The $5$ protons are there in atomic nuclei. A neutral atom has the same number of protons as well as the same number of electrons.

When we write the condensed form or abbreviated form of electronic configuration of boron, we have to start writing the noble gas configuration in the previous period, and then continue with the electronic configuration of the element in the new period. The noble gas symbol is enclosed in brackets. Then the next periods’ electronic configuration is added.

When it comes to the case of boron, it is in the ${2^{nd}}$ period of table, so that the noble gas will be helium, which is the noble gas in period $1$ . Since, the boron is in the group $13$ and the electronic configuration will be ending with $2s$ and $2p$ sublevels.

Note: The standard notation yields lengthy electronic configuration (which means the electronic configuration will be written as, ($Na = {\text{ }}1{s^2}2{s^2}2{p^6}3{s^1}$) . In those cases, condensed or an abbreviated notation is used instead of using standard electronic configuration. In condensed electron configuration, the sequence of completely filled subshell corresponds to the electronic configuration of a noble gas or inert gas is replaced with the symbol of that noble gas in a square bracket, $Na = {\text{ [Ne]}}\,3{s^1}$ .