Which isotope has 14 protons and 15 neutrons?

• A. Si-28
• B. N-29
• C. Si-29
• D. P-29

Answer: (C)

Verified step by step guidance

1. Identify the element by the number of protons. The number of protons defines the element's atomic number. Here, the isotope has 14 protons, so find the element with atomic number 14.
2. Recall that the element with 14 protons is Silicon (Si), since the atomic number 14 corresponds to Silicon on the periodic table.
3. Determine the mass number of the isotope by adding the number of protons and neutrons: \(\text{mass number} = \text{protons} + \text{neutrons} = 14 + 15\).
4. Write the isotope notation using the element symbol and the mass number: \(\text{Element}-\text{mass number}\). For this case, it will be \(\mathrm{Si}\) followed by the sum from the previous step.
5. Compare the options given to find the isotope that matches the element symbol and mass number calculated. The correct isotope is the one with 14 protons and a mass number equal to the sum of protons and neutrons.