Question

question 10 of 41
an atom of carbon has six protons, six electrons, and six neutrons.
what is the atomic mass of the carbon atom?
18, because the carbon atom has 18 subatomic particles
6, because the carbon atom has 6 electrons
6, because the carbon atom has 6 protons
12, because the carbon atom has 6 protons and 6 neutrons

Explanation:

Step1: Recall atomic mass definition

Atomic mass ≈ number of protons + number of neutrons

Step2: Calculate atomic mass

Protons = 6, neutrons = 6. So atomic mass = 6 + 6 = 12.

Step3: Evaluate options

Only the last option matches the calculation. Subatomic particles (including electrons) don’t contribute to atomic mass, electrons/protons alone don’t equal atomic mass.

Answer:

12, because the carbon atom has 6 protons and 6 neutrons