Question

_________have one or two electrons in their outer most shell *

a) p - block

b) s - block

c) d - block

d) f - block​

Answer 1

:A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in.[1] The term appears to have been first used by Charles Janet.[2] Each block is named after its characteristic orbital: s-block, p-block, d-block, and f-block.

The block names (s, p, d, and f) are derived from the spectroscopic notation for the value of an electron's azimuthal quantum number: sharp (0), principal (1), diffuse (2), or fundamental (3). Succeeding notations proceed in alphabetical order, as g, h, etc