	Time → (extent)
Left: a human molecular orbital view of the start reaction of the formation of the typical nuclear family at the day of first meeting of two human molecules, e.g. in their school orbitals, symbol S, say at about age 21, from American electrochemical engineer Libb Thims' 2007 Human Chemistry; right: an drawing of semi-orbital / semi-Venn diagram / semi-human chemical bond aspect of the self-visualized existence of a person named Paul, from American psychologist Ruthellen Josselson's 1996 book The Space Between Us. [3]

In human chemistry, nuclear family is a chemical aphorism (or chemical anthropomorphism) wherein the concept of the nucleus is used as a model or metaphor of the essential core of the human family, generally a pair of parents plus one or more orbiting children, just as the essential core of an atom is a pair of nuclides (bound protons and neutrons) plus one or more orbiting electrons.

Overview
The term “nuclear family” seems to have drifted into use in the 19th century, as can be found in a number of usages, following the circa 1846 non-atomic usage of the term “nuclear” meaning “of or like the nucleus of a cell”; after which following the discovery of the atomic nucleus in 1911 by Ernest Rutherford and his famous gold foil experiments, the term "nuclear family" transformed from a biological metaphor to a chemical metaphor, as can be found in number of usages in the decades to follow. [1]


The typical generic idea or conception of the nuclear family: one child and two parents.

The typical generic idea or conception of the nuclear family: one child and two parents.

The term “nuclear family”, in a dominant sense, is generally attributed to American anthropologist George Murdock and his 1949 book Social Structure, a term which forms the title of his opening chapter, in which he states: [2]

“The nuclear family is a social group characterized by common residence, economic cooperation, and reproduction. It includes adults of both sexes, at least two of whom maintain a socially approved sexual relationship, ...”

American electrochemical engineer Libb Thims' 2007 Human Chemistry textbook was the first to depict the so-called 2.5 child nuclear family in human molecular orbital theory terms. [3]

References
1. Nuclear – Online Etymology Dictionary.
2. Murdock, George. (1949). Social Structure (nuclear family, 54+ pgs). Free Press.
3. Thims, Libb. (2007). Human Chemistry (Volume One) (ch.9: Human Molecular Orbitals, pgs. 247-95). Morrisville, NC: LuLu.

External links
● Nuclear family – Wikipedia.