An atom with 17 protons belongs to which element?

An atom with 17 protons belongs to which element?

• A. Chlorine
• B. Argon
• C. Bromine
• D. Fluorine

Answer: (A)

The number of protons in the nucleus determines the element’s identity. Atomic number equals the count of protons. An atom with 17 protons has atomic number 17, which corresponds to chlorine. The other options have different numbers of protons (fluorine 9, argon 18, bromine 35), so they aren’t the element with 17 protons. Remember that isotopes and ions can change neutrons or electrons, but the element itself is fixed by the number of protons.

The number of protons in the nucleus determines the element’s identity. Atomic number equals the count of protons. An atom with 17 protons has atomic number 17, which corresponds to chlorine. The other options have different numbers of protons (fluorine 9, argon 18, bromine 35), so they aren’t the element with 17 protons. Remember that isotopes and ions can change neutrons or electrons, but the element itself is fixed by the number of protons.