An atom of the isotope ¹³C contains how many protons (p), neutrons (n), and electrons (e)?

• A. 7 protons, 6 neutrons, 7 electrons
• B. 7 protons, 7 neutrons, 6 electrons
• C. 6 protons, 7 neutrons, 6 electrons
• D. 6 protons, 6 neutrons, 7 electrons

Answer: (C)

Verified step by step guidance

1. Identify the atomic number of the element carbon (C). The atomic number corresponds to the number of protons in the nucleus of the atom. For carbon, the atomic number is 6, so it has 6 protons.
2. Understand that the isotope notation \( ^{13}\mathrm{C} \) indicates the mass number, which is the total number of protons and neutrons in the nucleus. Here, the mass number is 13.
3. Calculate the number of neutrons by subtracting the number of protons from the mass number using the formula: \( \text{neutrons} = \text{mass number} - \text{protons} \). For \( ^{13}\mathrm{C} \), this is \( 13 - 6 = 7 \) neutrons.
4. Determine the number of electrons in a neutral atom. Since the atom is neutral, the number of electrons equals the number of protons, which is 6 electrons for carbon.
5. Summarize the composition of the \( ^{13}\mathrm{C} \) isotope: 6 protons, 7 neutrons, and 6 electrons.