mass number: meaning, definition, pronunciation and examples
C2Technical/Scientific
Quick answer
What does “mass number” mean?
The total number of protons and neutrons in an atomic nucleus.
Audio
Pronunciation
Definition
Meaning and Definition
The total number of protons and neutrons in an atomic nucleus.
In nuclear physics and chemistry, a whole number representing the sum of protons and neutrons, used to distinguish isotopes of an element. It's approximately equal to the atomic mass but is always an integer.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage between British and American English in scientific contexts.
Connotations
Purely technical term with identical connotations in both varieties.
Frequency
Equally rare in general discourse; exclusively used in scientific/educational contexts in both regions.
Grammar
How to Use “mass number” in a Sentence
The mass number of [element/isotope] is [number].[Element] has a mass number of [number].Mass number = protons + neutrons.Vocabulary
Collocations
Examples
Examples of “mass number” in a Sentence
verb
British English
- This term is not used as a verb.
American English
- This term is not used as a verb.
adverb
British English
- This term is not used as an adverb.
American English
- This term is not used as an adverb.
adjective
British English
- The mass-number value is crucial for identification.
- Mass-number calculations require precision.
American English
- The mass-number designation appears as a superscript.
- Mass-number data was recorded in the lab notebook.
Usage
Meaning in Context
Business
Not used in business contexts.
Academic
Used in chemistry, physics, and nuclear science textbooks and research papers.
Everyday
Virtually never used in everyday conversation except in educational settings.
Technical
Essential term in nuclear physics, radiochemistry, and materials science for identifying isotopes.
Vocabulary
Synonyms of “mass number”
Vocabulary
Antonyms of “mass number”
Watch out
Common Mistakes When Using “mass number”
- Using 'mass number' interchangeably with 'atomic mass'.
- Writing it as one word ('massnumber').
- Forgetting it's always an integer.
FAQ
Frequently Asked Questions
No. Mass number is the total number of protons and neutrons (a whole number). Atomic mass is the weighted average mass of an element's isotopes measured in atomic mass units (often a decimal).
Typically as a superscript to the left of the element's symbol (e.g., ¹²C for carbon-12).
Yes, this is possible. For example, argon-40 and calcium-40 both have a mass number of 40 but different atomic numbers (proton counts).
Because it is a simple count of discrete particles (protons and neutrons), you cannot have a fraction of a nucleon in a nucleus.
The total number of protons and neutrons in an atomic nucleus.
Mass number is usually technical/scientific in register.
Mass number: in British English it is pronounced /ˈmæs ˌnʌmbə/, and in American English it is pronounced /ˈmæs ˌnʌmbər/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “No idioms exist for this technical term.”
Learning
Memory Aids
Mnemonic
Mass Number = Massive parts in the nucleus (protons + neutrons). Remember: MASSive things are counted with whole numbers.
Conceptual Metaphor
The nucleus as a crowded room where the mass number is the total number of people (protons and neutrons) present.
Practice
Quiz
What does the mass number represent?