Calcium has 20 protons, 20 neutrons, and 20 electrons. What is the atomic number of calcium?

A. 20
B. 40
C. 60

David Nuttall2008-09-15T09:13:22Z

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Count the protons to get the atomic number. So the answer is A: 20. 40 will be the atomic mass in this situation.

?2016-05-24T04:46:35Z

neutrons= 40-20=20 protons=20 electrons=20 neutrons=atomic mass- atomic number protons= atomic number electrons= same as protons.

Jewlzeh2008-09-15T08:56:40Z

The answer's 20. The atomic number is the amount of protons in one atom of the element. The atomic number of an element is on the periodic table, too.

Vincent P2008-09-15T08:54:54Z

It's 20. Atomic number refers to the number of protons in the atom.

one love2008-09-15T09:01:36Z

40

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