Question

unit 3 chem l test 2526
how does the radioactive isotope c - 14 differ from c - 12?
possible points: 4
it has a different number of protons and two less neutrons than c - 12
it has the same number of protons and two more electrons than c - 12
it has a different number of protons and two more neutrons than c - 12
it has the same number of protons and two more neutrons than c - 12

Explanation:

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. Carbon - 12 and carbon - 14 are isotopes of carbon. The number of protons in carbon is 6 for both C - 12 and C - 14. The mass number of C - 12 is 12 and of C - 14 is 14. Mass number = number of protons + number of neutrons. So C - 14 has 14 - 6=8 neutrons and C - 12 has 12 - 6 = 6 neutrons, meaning C - 14 has 2 more neutrons than C - 12.

Answer:

It has the same number of protons and two more neutrons than C - 12.