helium-4
UK[ˈhiːliəm fɔː]US[ˈhiːliəm fɔːr]
n
The most common and stable isotope of helium, having an atomic mass of 4 and a nucleus containing two protons and two neutrons.
Morpheme Breakdown
helium
4
helium
element
4
mass number
Etymology
The term is a modern scientific compound. 'Helium' originates from the Greek 'hēlios', meaning 'sun', as the element was first detected spectroscopically in the solar corona before being found on Earth. The '-4' is the mass number, a numerical identifier specifying this particular isotope's total count of protons and neutrons. The compound name 'helium-4' thus logically follows the systematic nomenclature in chemistry and physics, denoting the isotope of the element helium with a mass number of four. Its stability and abundance are central to nuclear fusion processes in stars and practical applications like cryogenics on Earth.
Analysis
Structure: helium (element) + 4 (mass number)
helium: From Greek 'hēlios' (sun), via New Latin. The name of the chemical element.
4: From Old English 'fēower'. A cardinal number indicating the atomic mass number of this specific isotope.
Examples
Helium-4 makes up nearly all of the naturally occurring helium on Earth.
The superfluid state is a remarkable property exhibited by liquid helium-4 at temperatures near absolute zero.
Scientists study helium-4 to understand fundamental principles of quantum mechanics and low-temperature physics.