Question 12

The atomic number of an atom that has 12 protons is 12.

The atomic number is defined as the number of protons in the nucleus of an atom. Since the atom in question has 12 protons, its atomic number is 12.

A) 1

Option A is incorrect because an atomic number of 1 corresponds to hydrogen, which has only one proton. Since the atom has 12 protons, it cannot have an atomic number of 1.

B) 144

Option B is incorrect as well. An atomic number of 144 would imply that the atom has 144 protons, which is not the case here. The atom only has 12 protons, making this option invalid.

C) 12

Option C is correct because the atomic number is equal to the number of protons in an atom. Since this atom has 12 protons, its atomic number is indeed 12.

D) 24

Option D is incorrect because an atomic number of 24 would mean that the atom has 24 protons. The atom in question has only 12 protons, thus this option does not apply.

Conclusion

The correct answer is 12, as it accurately reflects the number of protons in the atom. All other options fail because they either correspond to different elements with a different number of protons or misrepresent the atomic number of the atom in question. Therefore, option C is the only valid choice based on the given information.