1. What is Mass Number?

The mass number (symbol: A) of an atom is the total number of protons and neutrons (together known as nucleons) in its nucleus. It determines the isotope of an element.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Protons — Number of protons in the nucleus (atomic number)
• Neutrons — Number of neutrons in the nucleus

Explanation: The mass number is a count of nucleons (protons + neutrons) in an atom's nucleus.

3. Importance of Mass Number

Details: Mass number is fundamental in chemistry and physics as it identifies isotopes of an element. It's used in nuclear equations, radiometric dating, and understanding atomic structure.

4. Using the Calculator

Tips: Enter the number of protons (must be ≥1) and neutrons (must be ≥0). The calculator will sum them to give the mass number.

5. Frequently Asked Questions (FAQ)

Q1: Is mass number the same as atomic mass?
A: No, mass number is the count of nucleons (integer), while atomic mass is the weighted average of isotopes' masses (usually not an integer).

Q2: Can two different elements have the same mass number?
A: Yes, this is called isobars (e.g., argon-40 and calcium-40 both have mass number 40).

Q3: Why isn't electron count included?
A: Electrons contribute negligible mass compared to nucleons (protons+neutrons).

Q4: What's the typical range for mass numbers?
A: From 1 (hydrogen-1) to about 270 for the heaviest synthetic elements.

Q5: How does mass number relate to radioactivity?
A: Generally, elements with very high mass numbers (like uranium) tend to be radioactive.