Choose the correct option:
Which of the following is the correct electronic configuration of potassium.
Choose the correct option:
Which of the following is the correct electronic configuration of potassium.
The correct option is C 2, 8, 8, 1
The explanation for the correct option:
(c) Atomic number of Potassium (K) is 19
Step 1: Calculate the number of electrons in the atom of Potassium.
Atomic number= number of electrons in the neutral atom
Therefore, the Number of electrons in Potassium is 19.
Step 2: Fill these electrons in the orbits around the nucleus
Orbits or shells around the nucleus are filled as follows:
- The shells are filled in the order of their increasing energy i.e.; the lowest energy shell is filled first followed by the shell with higher energy and so on.
- The number of electrons that can be accommodated in a given shell is given by the 2n2 or Bohr-Bury scheme where n= number of orbits. Example: For the first orbit, n=1 and 2×12 =2 i.e.; two electrons can be accommodated in the first orbit.
- Electrons can not be filled in the next shell until the previous shell has been filled.
- The outermost orbit can accommodate a maximum of 8 electrons.
Step 3: Write the electronic configuration
The first or K shell can accommodate two electrons. Therefore, 2 electrons out of a total of 19 will occupy the innermost K shell.
The second or L shell can accommodate 8 electrons. Therefore, 8 electrons out of a total of 19 will occupy the innermost L shell.
The third or M shell can accommodate 18 electrons but due to the exceptionally low energy of the 4th shell, only 8 electrons are filled in the third shell and one electron goes to the N shell.
The fourth or N shell has 1 electron.
So the electronic configuration of Potassium is 2, 8, 8, 1.
The explanation for the incorrect option:
(a) 2, 8, 9: The third orbit cannot contain 9 electrons because this is not possible energetically.
(b) 8, 2, 9: This is not possible as the maximum capacity of the first shell is 2.
(d) 1, 2, 8, 8: This is not possible as electron filling cannot occur in the next shell until the first shell is filled. Here, the first shell has only one electron while its maximum capacity is 2. Also, for the second orbit, the maximum capacity is 8 whereas here, only 2 electrons are present.
Hence, option (c) is correct.
2, 8, 8, 1
The explanation for the correct option:
(c) Atomic number of Potassium (K) is 19
Step 1: Calculate the number of electrons in the atom of Potassium.
Atomic number= number of electrons in the neutral atom
Therefore, the Number of electrons in Potassium is 19.
Step 2: Fill these electrons in the orbits around the nucleus
Orbits or shells around the nucleus are filled as follows:
- The shells are filled in the order of their increasing energy i.e.; the lowest energy shell is filled first followed by the shell with higher energy and so on.
- The number of electrons that can be accommodated in a given shell is given by the 2n2 or Bohr-Bury scheme where n= number of orbits. Example: For the first orbit, n=1 and 2×12 =2 i.e.; two electrons can be accommodated in the first orbit.
- Electrons can not be filled in the next shell until the previous shell has been filled.
- The outermost orbit can accommodate a maximum of 8 electrons.
Step 3: Write the electronic configuration
The first or K shell can accommodate two electrons. Therefore, 2 electrons out of a total of 19 will occupy the innermost K shell.
The second or L shell can accommodate 8 electrons. Therefore, 8 electrons out of a total of 19 will occupy the innermost L shell.
The third or M shell can accommodate 18 electrons but due to the exceptionally low energy of the 4th shell, only 8 electrons are filled in the third shell and one electron goes to the N shell.
The fourth or N shell has 1 electron.
So the electronic configuration of Potassium is 2, 8, 8, 1.
The explanation for the incorrect option:
(a) 2, 8, 9: The third orbit cannot contain 9 electrons because this is not possible energetically.
(b) 8, 2, 9: This is not possible as the maximum capacity of the first shell is 2.
(d) 1, 2, 8, 8: This is not possible as electron filling cannot occur in the next shell until the first shell is filled. Here, the first shell has only one electron while its maximum capacity is 2. Also, for the second orbit, the maximum capacity is 8 whereas here, only 2 electrons are present.
Hence, option (c) is correct.
