Question

4.state true or false:
a) the electron configuration, for degenerate orbitals, the electrons start pairing up even before each of the degenerate orbitals get a share of a single electron.
b) in chemical reactions the valence electrons as well as core electrons are involved.
c) an s orbital is always spherical in shape and p orbital is always dumbbell shaped, irrespective of which principal energy level it is.

Explanation:

Part (a)

According to Hund's rule, for degenerate orbitals (orbitals with the same energy), electrons first occupy each degenerate orbital singly (with parallel spins) before pairing up. So the statement that electrons start pairing even before each degenerate orbital gets a single electron is incorrect.

In chemical reactions, only valence electrons (electrons in the outermost shell) are involved in bonding and reactions. Core electrons (electrons in inner shells) are not involved as they are tightly held by the nucleus. So the statement that both valence and core electrons are involved is incorrect.

The shape of an s - orbital is always spherical, and the shape of a p - orbital is always dumb - bell shaped, regardless of the principal energy level (n - value). For example, 1s, 2s, 3s orbitals are all spherical; 2p, 3p, 4p orbitals are all dumb - bell shaped. So this statement is correct.

Answer:

False

Part (b)