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प्रश्न
Explain the anomalous behaviour of chromium.
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उत्तर
- Chromium (Cr) has atomic number 24.
- Its expected electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d4.
- The 3d orbital is less stable, as it is not half-filled.
- Due to inter-electronic repulsion forces, one 4s electron enters into the 3d orbital. This makes the 4s and 3d orbitals half-filled, which gives extra stability, and the electronic configuration of Cr becomes 1s2 2s2 2p6 3s2 3p6 4s1 3d5.
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संबंधित प्रश्न
Using s, p, d notations, describe the orbital with the following quantum numbers n = 3; l =1.
Using s, p, d notations, describe the orbital with the following quantum numbers n = 4; l = 2.
Using s, p, d notations, describe the orbital with the following quantum numbers n = 4; l =3.
Give the names of quantum numbers.
Define the term Electronic configuration.
State the order of filling atomic orbitals following Aufbau principle.
Write orbital notations for the electron in orbitals with the following quantum numbers.
n = 4, l = 2
Write electronic configurations of \[\ce{Fe, Fe2+, Fe3+}\].
Write condensed orbital notation of electronic configuration of the following element:
Oxygen (Z = 8)
Write condensed orbital notation of electronic configuration of the following element:
Calcium (Z = 20)
Draw shapes of 2s orbitals.
Using the concept of quantum numbers, calculate the maximum numbers of electrons present in the ‘M’ shell. Give their distribution in shells, subshells, and orbitals.
Indicate the number of unpaired electron in:
Cr (Z = 24)
Total number of orbitals associated with third shell will be ______.
The pair of ions having same electronic configuration is ______.
Out of the following pairs of electrons, identify the pairs of electrons present in degenerate orbitals:
| (i) | (a) `n = 3, l = 2, m_l = -2, m_s = - 1/2` |
| (b) `n = 3, l = 2, m_l = -1, m_s = - 1/2` | |
| (ii) | (a) `n = 3, l = 1, m_l = 1, m_s = + 1/2` |
| (b) `n = 3, l = 2, m_l = 1, m_s = + 1/2` | |
| (iii) | (a) `n = 4, l = 1, m_l = 1, m_s = + 1/2` |
| (b) `n = 3, l = 2, m_l = 1, m_s = + 1/2` | |
| (iv) | (a) `n = 3, l = 2, m_l = +2, m_s = - 1/2` |
| (b) `n = 3, l = 2, m_l = +2, m_s = + 1/2` |
In which of the following pairs, the ions are iso-electronic?
(i) \[\ce{Na^{+}, Mg^{2+}}\]
(ii) \[\ce{Al3^{+}, O-}\]
(iii) \[\ce{Na+ , O2-}\]
(iv) \[\ce{N3-, Cl-}\]
Nickel atom can lose two electrons to form \[\ce{Ni^{2+}}\] ion. The atomic number of nickel is 28. From which orbital will nickel lose two electrons.
Calculate the total number of angular nodes and radial nodes present in 3p orbital.
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
1s, 2s, 3s, 2p
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
4s, 3s, 3p, 4d
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
5f, 6d, 7s, 7p
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, solve the questions given below:
Which of the following orbitals has the lowest energy?
5p, 5d, 5f, 6s, 6p
What is the difference between the terms orbit and orbital?
Match the quantum numbers with the information provided by these.
| Quantum number | Information provided |
| (i) Principal quantum number | (a) orientation of the orbital |
| (ii) Azimuthal quantum number | (b) energy and size of orbital |
| (iii) Magnetic quantum number | (c) spin of electron |
| (iv) Spin quantum number | (d) shape of the orbital |
Choose the INCORRECT statement
Which of the following is not the permissible arrangement of electrons in an atom?
Which of the following element do not follow Aufbau principle?
