Answer
Verified
437.4k+ views
Hint: Cr is the chromium element that belongs to the d-block. The last electron enters into the d-subshell. The d-orbital has the property of extra-stability because of a half-filled or fully-filled subshell.
Complete step by step answer:
Cr is the chromium element and it belongs to transition elements and is the element of d-block.
The atomic number of chromium is 24 and it belongs to the first series of the d-block.
According to the Aufbau principle the order of filling the electron in the orbital according to their increasing energies is: $\text{1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s}$
So, according to this order of filling the configuration of chromium must be:
$1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{4}}$.
But this is not the correct configuration of chromium.
The correct configuration of chromium can be explained by:
There are some exceptions in the first series in the electronic configuration of chromium (atomic no. = 24). It must be noted that unlike other elements of the first transition series, the chromium has 1 electron and is $4s-orbital$. This is due to the gain of additional stability by the atom by having a half-filled configuration (because the d-orbital has 5 subshells and each subshell has 1 electron) of $3d-orbital$. The $3d-orbital$in case of chromium gets exactly half-filled with configuration of $3{{d}^{5}}4{{s}^{1}}$. So, the configuration of chromium is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{5}}4{{s}^{1}}$.
Hence, the correct answer is an option (c)- $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{5}}4{{s}^{1}}$.
Note: In the first series of the transition metals the copper atom has also an exception in its configuration. The configuration of copper is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{1}}$. This is because the d-subshell has complete 10 electrons that have extra stability.
Complete step by step answer:
Cr is the chromium element and it belongs to transition elements and is the element of d-block.
The atomic number of chromium is 24 and it belongs to the first series of the d-block.
According to the Aufbau principle the order of filling the electron in the orbital according to their increasing energies is: $\text{1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s}$
So, according to this order of filling the configuration of chromium must be:
$1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{4}}$.
But this is not the correct configuration of chromium.
The correct configuration of chromium can be explained by:
There are some exceptions in the first series in the electronic configuration of chromium (atomic no. = 24). It must be noted that unlike other elements of the first transition series, the chromium has 1 electron and is $4s-orbital$. This is due to the gain of additional stability by the atom by having a half-filled configuration (because the d-orbital has 5 subshells and each subshell has 1 electron) of $3d-orbital$. The $3d-orbital$in case of chromium gets exactly half-filled with configuration of $3{{d}^{5}}4{{s}^{1}}$. So, the configuration of chromium is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{5}}4{{s}^{1}}$.
Hence, the correct answer is an option (c)- $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{5}}4{{s}^{1}}$.
Note: In the first series of the transition metals the copper atom has also an exception in its configuration. The configuration of copper is $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{1}}$. This is because the d-subshell has complete 10 electrons that have extra stability.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
Mark and label the given geoinformation on the outline class 11 social science CBSE
When people say No pun intended what does that mea class 8 english CBSE
Name the states which share their boundary with Indias class 9 social science CBSE
Give an account of the Northern Plains of India class 9 social science CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
Trending doubts
A group of fish is known as class 7 english CBSE
The highest dam in India is A Bhakra dam B Tehri dam class 10 social science CBSE
Write all prime numbers between 80 and 100 class 8 maths CBSE
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Onam is the main festival of which state A Karnataka class 7 social science CBSE
Who administers the oath of office to the President class 10 social science CBSE
Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE
Kolkata port is situated on the banks of river A Ganga class 9 social science CBSE
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE