Question

Identify the group of elements that corresponds to each of the following generalized electron configurations: (a) [noble gas] \(n s^{2} n p^{5}\) (b) [noble gas] \(n s^{2}(n-1) d^{2}\) (c) [noble gas] \(n s^{2}(n-1) d^{10} n p^{1}\) (d) [noble gas] \(n s^{2}(n-2) f^{6}\)

Short answer

(a) Group 17: Halogens (b) Group 4: Transition metals (c) Group 13 (d) Lanthanides and Actinides: Inner transition metals (f-block)

Step-by-step solution

(a) Identify the group for [noble gas] \(ns^2np^5\)

The elements with this electron configuration have two electrons in an s-orbital and five electrons in a p-orbital. The total number of valence electrons is 7. When we locate an element with 7 valence electrons in the periodic table, we find that they belong to Group 17, known as the halogens.

(b) Identify the group for [noble gas] \(ns^2(n-1)d^2\)

The elements with this electron configuration have two electrons in an s-orbital and two electrons in a d-orbital, which is one shell lower than their current outermost shell. The total number of valence electrons is 4. When we look for elements with 4 valence electrons in the periodic table, we find that they belong to Group 4 (transition metals).

(c) Identify the group for [noble gas] \(ns^2(n-1)d^{10}np^1\)

The elements with this electron configuration have two electrons in an s-orbital, a full d-orbital at the previous energy level, and one electron in a p-orbital. The total number of valence electrons is 3. When we search for elements with 3 valence electrons in the periodic table, we find that they belong to Group 13.

(d) Identify the group for [noble gas] \(ns^2(n-2)f^6\)

The elements with this electron configuration have two electrons in an s-orbital and six electrons in an f-orbital, which is two shells lower than their current outermost shell. These elements are part of the f-block, also known as the inner transition metals. Specifically, they belong to the lanthanides and actinides, which do not have a designated group number in the periodic table.