Question 28 (3 points) An atom of Si compared to an atom of Na has a larger (greater)? Check ALL that apply. Points deducted for incorrect answers. 1) number of protons 3) metallic character 4) atomic size

\[ \textbf{Step 1: Compare the number of protons.} \] Sodium (\(\text{Na}\)) has an atomic number of 11, meaning it has 11 protons. Silicon (\(\text{Si}\)) has an atomic number of 14, meaning it has 14 protons. Since \(14 > 11\), an atom of \(\text{Si}\) has a greater number of protons than an atom of \(\text{Na}\). Thus, option (1) is correct. \[ \textbf{Step 2: Compare the metallic character.} \] Metallic character indicates how readily an atom loses electrons. \(\text{Na}\) is an alkali metal and exhibits strong metallic character. \(\text{Si}\) is a metalloid and does not have as pronounced metallic properties. Therefore, an atom of \(\text{Si}\) does not have a greater metallic character than an atom of \(\text{Na}\). Thus, option (3) is incorrect. \[ \textbf{Step 3: Compare the atomic size.} \] Both \(\text{Na}\) and \(\text{Si}\) are in the same period (Period 3). Within the same period, atomic size decreases from left to right due to increasing effective nuclear charge. Since \(\text{Na}\) is to the left of \(\text{Si}\), \(\text{Na}\) has a larger atomic size than \(\text{Si}\). Thus, an atom of \(\text{Si}\) does not have a larger atomic size compared to \(\text{Na}\). So option (4) is incorrect. \[ \textbf{Final Answer: Only option (1) is correct.} \]