Question

(b) (i) Carbon-12 is a stable isotope. Carbon-14 is an unstable radioactive isotope.

Table 12.2 shows the contents of each nucleus.
Carbon-12
Carbon-14
Number of protons
6
6
Number of neutrons
6
8
Table 12.2
Explain why carbon-12 and carbon-14 are isotopes.
[1]

Answer 1

Isotopes are two or more elements with the same number of protons, but different number of neutrons.

So Carbon-12 and Carbon-14 has 6 protons, however Carbon-12 has 6 neutrons and Carbon-14 has 8 neutrons. They have different number of 'neutrons' thus they are isotopes