Briefly explain why electronic configurations of lanthanoids are not known with certainty.

In the lanthanoids, 4f and 5d subshells are very close in energy. The outermost 6s-orbital remains filled with two electrons (6s2) . The electrons can easily jump from 4f to 5d or vice-versa. Further, irregularities in electronic configurations are also […]

Explain the meaning of inner transition series.

i. The last electron in the f-block elements enters into (n-2) f-orbitals, i.e., inner to the penultimate energy level and they form a transition series within the transition series (d-block elements). Hence, the f-block elements are known as inner transition […]

Define ionization enthalpy. Explain the trends observed in the ionization enthalpies of the d-block elements.

Definition of ionization enthalpy. Ionization enthalpy is defined as the amount of energy required to remove the outermost electron completely from a gaseous atom in its ground state. Explanation of ionization enthalpies of the d-block elements. i. The ionization enthalpies of […]

Explain the metallic characters of the d-block elements.

i. All the transition elements are metallic in nature. They either have hexagonal close pack (hcp), cubic close pack (ccp) or body centred cubic lattices which is a characteristic of true metal. ii. They are hard, lustrous, malleable and ductile […]

Explain the position of d-block elements in the periodic table.

Position of d-block elements in the periodic table: i. The d-block elements lie in between s- and p-block elements, i.e., these elements are located in the middle part of the periodic table. ii. The d-block elements are present in 4th […]

What is a polaroid?

       A large sheet of synthetic material packed with tiny crystals of a dichroic substance oriented parallel to one another so that it transmits light only in one direction of the electric vector is called a polaroid.   […]

State Brewster’s law.

The tangent of the polarising angle is equal to the refractive index of the refracting medium at which partial reflection takes place. According to Brewster’s law, tan ip = μ  State the main uses of polaroids. For Question and answer […]