Which period 3 metal is more reactive than magnesium?

• A. Aluminum
• B. Sodium
• C. Phosphorus
• D. Silicon

Answer: (B)

Verified step by step guidance

1. Identify the elements in period 3 of the periodic table: Sodium (Na), Magnesium (Mg), Aluminum (Al), Silicon (Si), Phosphorus (P), Sulfur (S), Chlorine (Cl), and Argon (Ar).
2. Recall that reactivity for metals generally decreases across a period from left to right because atoms hold their electrons more tightly as nuclear charge increases.
3. Recognize that Magnesium (Mg) is a group 2 metal, and Sodium (Na) is a group 1 metal, which is to the left of Magnesium in period 3.
4. Understand that group 1 metals (alkali metals) are more reactive than group 2 metals (alkaline earth metals) because they lose one electron more easily than group 2 metals lose two electrons.
5. Conclude that Sodium (Na), being a group 1 metal in period 3, is more reactive than Magnesium (Mg).