Question

Which statement about the number of protons and neutrons in the atoms of the isotopes of carbon 12C , 13C, 14C is correct?

(Atomic number of chlorine is 6.)

Answer 1

A.
Because isotopes vary only in the number of neutrons, all three isotopes have 6 protons. 12C has 12 neutrons, 13C has 13 neutrons, and 14C has 14 neutrons.

B.
Because isotopes vary only in the number of protons, all three isotopes have 6 neutrons. 12C has 6 protons, 13C has 7 protons, and 14C has 8 protons.

C.
Because isotopes vary only in the number of protons, all three isotopes have 6 neutrons. 12C has 12 protons, 13C has 13 protons, and 14C has 14 protons.

D.
Because isotopes vary only in the number of neutrons, all three isotopes have 6 protons. 12C has 6 neutrons, 13C has 7 neutrons, and 14C has 8 neutrons.

Answer 2

Not sure I understand this, I'd appreciate an explanation.
:)

Answer 3

The answer is D. What determines an element is the number of PROTONS. The number of NEUTRONS can vary, making an ISOTOPE. 12C has 6 PROTONS and 6 NEUTRONS. 14C has 6 PROTONS and 8 NEUTRONS, but will eventually decay down to the more stable 12c (this is how radio carbon dating works). I'm going to ignore where you put chlorine in there cause I assume it's a typo.

Answer 4

@pking Thanks for your help! I aced the test. :D