Answer
409.8k+ views
Hint: Electronic configuration: The distribution of electrons of atoms and molecules in its atomic orbital is termed as Electronic configuration. There are four kinds of atomic orbitals present s, p, f, d. The electrons in atomic orbitals are filled according to order of their increasing energy.
Complete step by step answer:
The increasing order of atomic orbital in context with energy is given by Aufbau principle. Example: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…..
According to Aufbau principle, electronic configuration of $Mo(Z=42)$is:
Atomic number (Z) = 42
Electronic Configuration: $1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}},5{{s}^{2}},4{{d}^{4}}$
But, to attain stability the actual electronic configuration of $Mo(Z=42)$is $1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}},5{{s}^{1}},4{{d}^{5}}$ i.e. one electron of s-orbital jumps into d-orbital because half filled orbital is more stable. Now to avoid extra length we convert the electronic configuration to noble gas electronic configuration:$[1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}}],5{{s}^{1}},4{{d}^{5}}$
The outer E. C. is: $[Kr]5{{s}^{1}}4{{d}^{5}}$
So, the correct answer is “Option B”.
Note:
The total no. of protons present in an atom gives the atomic no. of an element. The mass no. is given by the sum of protons and neutrons so we can easily find no. of neutrons by subtracting atomic no. from mass no. of a particular element. One should be familiar with Aufbau principle i.e. electrons first occupy the lowest energy orbital available to them and enter higher energy orbitals only when the lower energy orbitals are filled. The name of the noble gas should be put into the square bracket i.e. [ ].
Complete step by step answer:
The increasing order of atomic orbital in context with energy is given by Aufbau principle. Example: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…..
According to Aufbau principle, electronic configuration of $Mo(Z=42)$is:
Atomic number (Z) = 42
Electronic Configuration: $1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}},5{{s}^{2}},4{{d}^{4}}$
But, to attain stability the actual electronic configuration of $Mo(Z=42)$is $1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}},5{{s}^{1}},4{{d}^{5}}$ i.e. one electron of s-orbital jumps into d-orbital because half filled orbital is more stable. Now to avoid extra length we convert the electronic configuration to noble gas electronic configuration:$[1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}},3{{d}^{10}},4{{p}^{6}}],5{{s}^{1}},4{{d}^{5}}$
The outer E. C. is: $[Kr]5{{s}^{1}}4{{d}^{5}}$
So, the correct answer is “Option B”.
Note:
The total no. of protons present in an atom gives the atomic no. of an element. The mass no. is given by the sum of protons and neutrons so we can easily find no. of neutrons by subtracting atomic no. from mass no. of a particular element. One should be familiar with Aufbau principle i.e. electrons first occupy the lowest energy orbital available to them and enter higher energy orbitals only when the lower energy orbitals are filled. The name of the noble gas should be put into the square bracket i.e. [ ].
Recently Updated Pages
Mark and label the given geoinformation on the outline class 11 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
When people say No pun intended what does that mea class 8 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Name the states which share their boundary with Indias class 9 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give an account of the Northern Plains of India class 9 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Advantages and disadvantages of science
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Bimbisara was the founder of dynasty A Nanda B Haryanka class 6 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Which are the Top 10 Largest Countries of the World?
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
10 examples of evaporation in daily life with explanations
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
How do you graph the function fx 4x class 9 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)