Question

multiple - choice question

1. which \block\ is helium part of?

b. p
d. f
a. s
c. d

Explanation:

Helium (\(He\)) has an electron configuration of \(1s^{2}\). In the periodic table, the \(s -\)block elements have their outermost electrons in \(s -\)orbitals. Helium, despite being a noble gas (usually thought of with \(p -\)block noble gases like \(Ne\), \(Ar\) etc. which have \(ns^{2}np^{6}\) configurations for \(n\geq2\)), has its valence electrons in the \(s -\)orbital (\(1s\) in this case). The \(p -\)block elements have their valence electrons in \(p -\)orbitals (\(ns^{2}np^{x}\), \(x = 1 - 6\) for \(n\geq2\)), \(d -\)block elements have \( (n - 1)d^{x}ns^{y}\) (\(x=1 - 10\), \(y = 0 - 2\)) and \(f -\)block elements have \( (n - 2)f^{x}(n - 1)d^{0 - 1}ns^{2}\) configurations.

Answer:

a. s