Why spdf stands in the periodic table?

Answer 1

s,p,d and f are designations for the four different types of subshells.

s is spherical in shape and has only one orientation in three dimensional space.

p has a dumbbell shape and has three orientations:

Px, Py and Pz.

d has a double dumbbell shape and has 5 orientations. Dxy, Dyz, Dxz, Dx2-y2, Dz2

f has a complex shape and has 7 orientations.

Each orbital can hold 2 electrons. s having only 1 orientation can hold only 2 electrons. p having 3 orientations, has 3 orbitals, each having the capacity to hold 2 electrons, so it can totally hold (3X2=) 6 electrons.

Similarly d can hold (5X2=) 10 electrons and f can hold (7X2=) 14 electrons.

The letters s, p, d, f respectively stand for sharp, principal, diffused and fundamental.

In the Periodic Table depending on which sub-shell is the valence shell (outermost) we have the spdf blocks.

The s-block is the alkali metals and alkaline earth metals.

The p-block is the non-metals and metalloids.

The d-block has the transition metals.

The f-block has lanthanides and actinides(mostly radioactive).

Answer 2

The letters s, p, d, and f refer to different types of electron orbitals in an atom. They represent different shapes and orientations of where electrons are likely to be found. These orbitals help to define the energy levels and properties of the elements in the periodic table.