Question

Which of the following statements related to the modern periodic table is incorrect?

• A. The p-block has 6 columns, because a maximum of 6 electrons can occupy all the orbital in a p-shell.
• B. The d-block has 8 columns, because a maximum of 8 electrons can occupy all the orbital in a d-sub shell.
• C. Each block contains a number of columns equal to the number of electrons that can occupy that sub shell.
• D. The block indicates value of Azimuthal quantum number (l) for the last sub shell that received electrons in building up the electronic configuration.

Answer 1

The correct option is B

The d-block has 8 columns, because a maximum of 8 electrons can occupy all the orbital in a d-sub shell.

Do you remember for azimuthal quantum number $\left(l\right)$ = 2, how many orbitals were possible?

5 orbitals are possible for $l$ = $2$.

These are d-orbitals and they are degenerate orbitals.

According to the Aufbau principle, maximum 2 electrons can be present in an orbital and they will have opposite spin.

Therefore d-orbitals can accommodate $5\times 2$ = $10electrons$

Now because d-orbital can accommodate $10electrons$ and also the periodic table is arranged in the increasing order of atomic numbers from left to right in a period, there should be $10columns$ (groups) for d-block elements.

Similarly, p-block has 6 columns because p orbital can accommodate 6 electrons. Therefore, we can generalise that each block contains, a number of columns equal to the number of electrons that can occupy in that sub shell.

The statement the block indicates value of azimuthal quantum number (l) for the last sub shell that received electrons in building up the electronic configuration is also true of the periodic table.