Which of the following best describes an atom that has fewer neutrons than protons and more electrons than protons?

• A. A positively charged ion (cation) with more neutrons than protons
• B. A negatively charged ion (anion) with a mass number less than twice its atomic number
• C. A neutral atom with equal numbers of protons, neutrons, and electrons
• D. An isotope with more protons than electrons and neutrons

Answer: (B)

Verified step by step guidance

1. Identify the key characteristics of the atom described: it has fewer neutrons than protons, and more electrons than protons.
2. Recall that the number of protons defines the atomic number (Z), and the number of neutrons plus protons gives the mass number (A). Since neutrons < protons, the mass number A is less than twice the atomic number Z.
3. Understand that having more electrons than protons means the atom has gained extra electrons, resulting in a negative charge, which defines an anion.
4. Combine these observations: the atom is negatively charged (anion) and has a mass number less than twice its atomic number due to fewer neutrons than protons.
5. Compare these conclusions with the given options to select the one that best matches the description.