Based on periodic trends in metallic character, which of the following elements is expected to be the most chemically reactive?

• A. Mg (magnesium)
• B. Si (silicon)
• C. Na (sodium)
• D. Al (aluminum)

Answer: (C)

Verified step by step guidance

1. Understand that metallic character refers to how readily an element can lose electrons to form positive ions, which is closely related to chemical reactivity in metals.
2. Recall that metallic character increases as you move down a group (column) in the periodic table because atoms have more electron shells, making it easier to lose outer electrons.
3. Also remember that metallic character decreases as you move from left to right across a period (row) because atoms have more protons, increasing effective nuclear charge and holding electrons more tightly.
4. Identify the positions of the elements: Na (sodium) is in Group 1 and Period 3, Mg (magnesium) is in Group 2 and Period 3, Al (aluminum) is in Group 13 and Period 3, and Si (silicon) is in Group 14 and Period 3.
5. Compare their metallic characters based on their group positions: since Na is furthest to the left in Period 3, it has the highest metallic character and thus is expected to be the most chemically reactive among the given elements.