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  2. /Chemistry
  3. /Unit 1: Some Basic Concepts in Chemistry
  4. /Question

Chemistry · Concept of atom, molecule, element and compound

4 protons, 5 neutrons, and 4 electrons are there in an atom of beryllium. Its ma

4 protons, 5 neutrons, and 4 electrons are there in an atom of beryllium. Its mass number is:

  • A. 10
  • B. 5
  • C. 8
  • D. 9

Step-by-step solution

Mass number = number of protons + number of neutrons = 4 + 5 = 9.
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