In periodic table why blocks are named as s p d f?

There are 4 types of orbitals : namely s, p, d and f.

In the Periodic Table, except hydrogen, the ground state electronic configuration of an element has one more electron than that of its previous element. Elements are classified into blocks according to what type of electron that an element exceeds its previous element.

For each element in the s block of the Periodic Table, the element has one s electron more than its previous element. For example, the electronic configuration of Na is [Ne] 3s¹, which has one s electron more than that of its previous element Ne, so that Na is classified as an s-block element. One more example, the electronic configuration of Mg is [Ne] 3s², which has one s electron more than that of its previous element Na, so that Mg is also classified as an s-block element.

For each element in the p block of the Periodic Table, the element has one p electron more than its previous element. For example, the electronic configuration of S is [Ne] 3s² 2p⁴ and that of Cl is [Ne] 3s² 2p⁵. Cl has one p electron more than its previous element S, so that Cl is classified as a p block element.

Similarly, for each element in the d block of the Periodic Table, the element has one d electron more than its previous element. Also, for each element in the f block of the Periodic Table, the element has one f electron more than its previous element.

It is based on the electronic configuration of the elements

Spdf Periodic Table Blocks

Aren't they shape of orbitals like sphere and so ?

The orbitals are -

S for spherical. Up to 2 electrons each.

P for perpendicular. Up to 6 electrons each.

D for (the name meanings break here) transition. Up to 10 electrons each.

F for Lanthenides. Up to 14 electrons each.

The pattern across is each letter has 4 more than the previous. It's why the table has steps.

DrBob1 said:

"Sharp, "Principal", "Diffuse", and "Fundamental"

Knowledge of orbitals comes from a consideration of the spectrum of an element and the behavior of the lines (splitting in a magnetic field or being shifted from a calculated position). Different types of lines were named sharp, principal, etc. If you wanted to know exactly which types of lines were named what, you'd have to delve into some of the specialized historical literature. The spdf notation is simply homage to the past. Another example of this are K-lines and L-lines in x-ray spectra:

https://en.wikipedia.org/wiki/K-alpha

The letters are initials of "Sharp, "Principal", "Diffuse", and "Fundamental". Many years ago, these must have meant something.

These are the sublevels of the outer energy level that the last electron (the differentiating electron) is in for that element.