Which of the following elements exhibits the greatest metallic character and is therefore the most reactive metal?

• A. Mg (magnesium)
• B. Al (aluminum)
• C. K (potassium)
• D. Na (sodium)

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 related to its reactivity as a metal.
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. Recall that metallic character decreases as you move from left to right across a period (row) because atoms have more protons, increasing the effective nuclear charge and holding electrons more tightly.
4. Identify the positions of the elements in the periodic table: K (potassium) and Na (sodium) are in Group 1 (alkali metals), Mg (magnesium) is in Group 2, and Al (aluminum) is in Group 13.
5. Compare the elements based on their group and period: since K is below Na in Group 1, it has a greater metallic character and is more reactive than Na, Mg, and Al.