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

• A. K
• B. Al
• C. Na
• D. Mg

Answer: (A)

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 chemical 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) in the periodic table because atoms hold their electrons more tightly.
4. Identify the positions of the elements: K (potassium) and Na (sodium) are in Group 1, Mg (magnesium) is in Group 2, and Al (aluminum) is in Group 13. Among these, K is below Na in Group 1, so it has a larger atomic radius and lower ionization energy.
5. Conclude that since K is lower in Group 1 than Na, and Group 1 elements are more metallic than Groups 2 and 13, K exhibits the greatest metallic character and is the most chemically reactive metal among the options.