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Home Concept Builders Elements, Atoms, and Ions Isotopes Help Help 2

Isotopes - Questions 2 Help

Every atom of the element carbon has 6 protons. This is carbon's atomic number. But the number of neutrons in the atoms of carbon can differ from atom to atom. Most atoms of carbon have 6 neutrons. But other atoms have carbon have 7 or 8 neutrons. These different forms of carbon atoms are known as isotopes. They are referred to as carbon-12, carbon-13, and carbon-14. The numbers 12, 13, and 14 are known as the mass number of these three isotopes. It indicates the number of protons and neutrons (the sum) in the nucleus of their atoms.

There is just one question in this Question Group. Each time the question appears, the answer options are presented in a scrambled order.
 

Version 1:
The mass number of an isotope refers to the _____.
number of protons present in an atom
number of neutrons present in an atom
number of electrons present in an atom
number of protons and neutrons present in an atom
number of protons and electrons present in an atom

Like any course, a Chemistry course has a set of vocabulary terms that you just need to know. An understanding of the vocabulary becomes foundational to progress in the course. This question tests your knowledge of the term mass number. The questions in the subsequent activities of this Concept Builder will test your ability to make meaning of it and use it. If you look up in the Fundamentals section of this page, you will see the definition of mass number. But before you go answer the question, we suggest that you record a note in an accessible location that you can make frequent reference to until you gain a comfort with the meaning of mass number.

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