Question

How do you write the condensed electron configurations for the following atoms using the appropriate noble-gas core abbreviations?
1)$C$
2)$Ni$
3) $Se$
4)$Cd$
5)$U$
6)$Pb$

Answer 1

Hint The answer here includes the concept of shorthand notations of elements which is nothing but writing the valence electrons outside preceded by writing the remaining electronic configuration of the respective noble gas.

Complete step – by – step answer:
In the classes of chemistry, we have studied the basic concepts dealing with writing the electronic configuration of an atom in the common form as well as abbreviated form with the help of noble gas configuration.
Let us now see the abbreviated form of all the given elements.
The abbreviated form of writing the electronic configuration using the noble gas core is called the shorthand notations.
-Let us write these notations for the given elements one by one with the help of their atomic number.

1. $C$ is the symbol given for the carbon atom which has the atomic number 6 and electronic configuration $1{{s}^{2}}2{{s}^{2}}2{{p}^{4}}$, the valence electrons here is in 2s and 2p orbitals which is written outside. The remaining 1s configuration is of the configuration of noble gas Helium.
   Thus shorthand notation for carbon is $[He]2{{s}^{2}}2{{p}^{4}}$
   Similarly for 2) $Ni$ has the atomic number 28 and therefore it is near to the noble gas configuration of argon and therefore the notation is $[Ar]3{{d}^{8}}4{{s}^{2}}$
   3)$Se$ has atomic number 34 which is near to the noble gas configuration of argon and therefore the notation is $[Ar]3{{d}^{10}}4{{s}^{2}}4{{p}^{4}}$
   4)$Cd$ has atomic number 48 and thus is near to the noble gas configuration of krypton and therefore the notation is $[Kr]4{{d}^{10}}5{{s}^{2}}$
2. $U$ has atomic number 92 which is near to the noble gas configuration of radon and the notation will be $[Rn]5{{f}^{3}}6{{d}^{10}}7{{s}^{2}}$
3. $Pb$ with atomic number 82 and is near to the noble gas configuration of Xenon which has the notation $[Xe]4{{f}^{14}}5{{d}^{10}}6{{s}^{2}}6{{p}^{2}}$

Note: Note that the valence electrons are nothing but the electrons in outermost orbit and the shorthand notations of the elements are written to understand the valence electrons easily of the given particular atom.