Final answer:
The atom described has 11 protons, 11 electrons, and 12 neutrons.
Step-by-step explanation:
The atom described has a mass number of 23 and an atomic number of 11. The mass number represents the sum of protons and neutrons, while the atomic number represents the number of protons.
Therefore, in this atom, the number of protons is 11, the number of electrons is also 11 (since atoms are electrically neutral), and the number of neutrons can be calculated by subtracting the atomic number from the mass number. Hence, the number of neutrons is 12.
So, the correct answer is B. 11, 11, 12. An atom with a mass number of 23 and an atomic number of 11 has 11 protons, which is determined directly by the atomic number. Since the mass number is the sum of protons and neutrons, there are 23 - 11 = 12 neutrons in the atom. In a neutral atom, the number of electrons is equal to the number of protons, so it has 11 electrons. Therefore, the correct answer is B. 11 protons, 11 electrons, 12 neutrons.