Properties of a Technetium (Tc) Atom

Steps:

• Identify Tc's atomic number: 43 protons in neutral atom.
• For neutral atom, electrons equal protons: 43 electrons.
• Common isotope Tc-99 has 43 protons + 56 neutrons = 99 nucleons.
• Evaluate each statement against these facts.

Why D is correct:

• Not enough information (statement D is missing/ambiguous).

Why the others are wrong:

• A: Tc-99 has 56 neutrons (13 more than 43 protons), but statement says "13 fewer protons than neutrons," which reverses the relation.
• B: Neutral Tc atom has 43 electrons, not 45; phrasing "it forms Tc" is unclear but electron count is incorrect.
• C: Tc-99 has 99 nucleons, not 56.

Final answer: D