mass number
mass number — noun
1. the number you get by adding together all the protons and all the neutrons in a
the number you get by adding together all the protons and all the neutrons in a single atom's centre — this whole number identifies which isotope of an element you have
Shirin's chemistry teacher asked the class to calculate the mass number of carbon-14.
mass number of [element-isotope]
Léa wrote down that oxygen-16 has a mass number of sixteen.
has a mass number of [number]
Bao checked the periodic table but could not find the mass number listed anywhere.
The mass number of uranium-235 is two hundred and thirty-five, Faisal explained.
Gabriel remembered that the mass number equals protons plus neutrons in the nucleus.
- nucleon number
more formal and used mainly in physics contexts
文法句型
mass number of + [element/isotope]
用法筆記
A technical term in chemistry and physics. Do not confuse with atomic weight, which averages the mass numbers across all naturally occurring isotopes of an element.