Start learning →

The mass number of an atom is the sum of its protons and:

ANeutrons
BElectrons
CPositrons
DNucleotides
Answer & Solution
Correct answer: A. Neutrons
1. Electrons are far too light to count. 2. Only nuclear particles matter here. 3. It is protons plus neutrons. _Source: syllabus Science, Ch 4 'Structure of the Atom'_
Practise this question with Quill — CBSE Class 9 →

Keep practising Structure of the Atom

Browse all Structure of the Atom questions for CBSE Class 9, or explore more Science topics.

Start a Structure of the Atom lesson →
Related questions
Pick the right answer, quicklySpot the one that does not fitIsotope or isobar?Fill the gaps on atomic structureTrue or false about the atomSort each particle by where it sitsOrder the gold foil experimentMatch each scientist to the discovery