Which isotope has 13 protons and 14 neutrons?

• A. Aluminum-27 (Al-27)
• B. Magnesium-27 (Mg-27)
• C. Aluminum-26 (Al-26)
• D. Silicon-27 (Si-27)

Answer: (A)

Verified step by step guidance

1. Identify the element by the number of protons. The number of protons defines the atomic number and thus the element. Here, 13 protons correspond to the element Aluminum (Al).
2. Determine the mass number of the isotope by adding the number of protons and neutrons: \(\text{mass number} = \text{protons} + \text{neutrons} = 13 + 14\).
3. Write the isotope notation using the element symbol and the mass number, which is the sum of protons and neutrons. For example, Aluminum with mass number 27 is written as \(^{27}\text{Al}\).
4. Compare the calculated isotope with the given options to find the correct match based on the number of protons (element) and the mass number.
5. Confirm that the isotope with 13 protons and 14 neutrons is Aluminum-27 (\(^{27}\text{Al}\)), as it matches both the element and the mass number.