Outermost electronic configurations of four elements A,B,C,D are given below:
(A) 3s2 (B) s23p1 (C) 3s23p3 (D) 3s23p4
The correct order of fist ionization enthalpy for them is:
The correct answer is (B): (B)< (A)< (D)< (C)
Orbitals with fully filled and half-filled electronic configuration are stable, and require more energy for ionization
Elements with greater electronegativity require more energy for ionisation
List-I Tetrahedral Complex | List-II Electronic configuration |
---|---|
(A) TiCl4 | (I) e2, t20 |
(B) [FeO4]2- | (II) e4, t23 |
(C) [FeCl4]- | (III) e0, t22 |
(D) [CoCl4]2- | (IV) e2, t23 |
Electronic configuration, also called electronic structure, the arrangement of electrons in energy levels around an atomic nucleus. According to the older shell atomic model, electrons occupy several levels from the first shell nearest the nucleus, K, through the seventh shell, Q, farthest from the nucleus. Electrons have to be filled in the s, p, d, f in accordance with the following rule.For example, the electron configuration of sodium is 1s22s22p63s1.
Maximum number of electrons that can be accommodated in a shell is based on the principal quantum number (n). It is represented by the formula 2n2, where ‘n’ is the shell number.
1. Aufbau’s principle: The filling of electrons should take place in accordance with the ascending order of energy of orbitals:
2. Pauli’s exclusion principle: No two electrons can have all the four quantum numbers to be the same or if two electrons have to be placed in an energy state they should be placed with opposite spies.
3. Hund’s rule of maximum multiplicity: In the case of filling degenerate (same energy) orbitals, all the degenerate orbitals have to be singly filled first and then only pairing has to happen.