Mass Number vs Atomic Number — Difference (with Table)
Mass Number vs Atomic Number compared side by side — a 6-row comparison table and 4 key points. Class 9 Chemistry, free and no sign-up.
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TL;DR: Mass Number vs Atomic Number compared side by side — a 6-row comparison table and 4 key points. Class 9 Chemistry, free and no sign-up.
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The main difference between Mass Number and Atomic Number: The atomic number is the number of protons in an atom's nucleus and defines the element, while the mass number is the total of protons and neutrons. Both n
Mass Number vs Atomic Number — Comparison Table
| Basis | Mass Number | Atomic Number |
|---|---|---|
| Definition | Total protons and neutrons in nucleus | Number of protons in nucleus |
| Symbol | Represented as A | Represented as Z |
| Determines | Mass of atom | Identity of element |
| Variation in Isotopes | Differs between isotopes | Same for all isotopes of an element |
| Calculation | A = Protons + Neutrons | Z = Number of Protons |
| Example | Carbon-12 has mass number 12 | Carbon has atomic number 6 |
Key Points
- Atomic number uniquely identifies an element while mass number helps identify specific isotopes
- The number of neutrons equals mass number minus atomic number
- Atoms of the same element always have the same atomic number but can have different mass numbers
- Atomic number determines chemical properties while mass number affects physical properties