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

• A. Mg
• B. Al
• C. Na
• D. Si

Answer: (C)

Verified step by step guidance

1. Recall that metallic character refers to how readily an element loses electrons to form positive ions, which is closely related to reactivity in metals.
2. Understand that metallic character increases as you move down a group in the periodic table because atoms have more electron shells, making it easier to lose electrons.
3. Also, metallic character decreases as you move from left to right across a period 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, Period 3; Mg (magnesium) is in Group 2, Period 3; Al (aluminum) is in Group 13, Period 3; Si (silicon) is in Group 14, Period 3.
5. Since Na is furthest to the left in the periodic table among the given elements, it has the highest metallic character and thus is the most reactive metal in this group.