Which of the following is the composition of an isotope of calcium (atomic number 20)?

22 protons, 20 neutrons, 19 electrons

19 protons, 20 neutrons, 19 electrons

20 protons, 25 neutrons, 20 electrons

21 protons, 20 neutrons, 20 electrons

sorry i asked this question like 2 times. i just really need the answer!! i thought calcium had 20 protons and 20 neutrons but there is no option like that :( so confused, please help!

1 Answer

  • 7 years ago

    A calcium Atom needs to have 20 atoms. It's atomic number gives that away. the number of neutrons can vary. That's where the word "isotope" comes in. An atom can have many isotopes with the same number of PROtons but a different number of NEUtrons

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