How many protons are present in the nucleus of a sodium (Na) atom?

• A. 10
• B. 11
• C. 23
• D. 12

Answer: (B)

Verified step by step guidance

1. Identify the element in question, which is sodium (Na). Each element is defined by its atomic number, which represents the number of protons in its nucleus.
2. Recall that the atomic number of sodium (Na) is 11. This number is unique to sodium and can be found on the periodic table.
3. Understand that the number of protons in the nucleus of an atom is equal to the atomic number of the element.
4. Therefore, the number of protons in a sodium atom is equal to its atomic number, which is 11.
5. Note that the other numbers given (10, 12, 23) could represent neutrons or mass number, but only the atomic number corresponds to the number of protons.