How many protons do all isotopes of copper (Cu) have?

• A. 29
• B. 30
• C. 63
• D. 35

Answer: (A)

Verified step by step guidance

1. Recall that the number of protons in an element is defined by its atomic number, which is unique to each element.
2. Identify copper (Cu) on the periodic table and find its atomic number. This number represents the number of protons in every atom of copper.
3. Understand that isotopes of an element differ in the number of neutrons, not protons, so all isotopes of copper have the same number of protons.
4. Note that the atomic number of copper is 29, meaning every copper atom, regardless of isotope, contains 29 protons.
5. Therefore, the answer to how many protons all isotopes of copper have is the atomic number of copper, which is 29.