Question

The correct order of increasing metallic character of \(Na\), \(Be\), \(Mg\), \(Si\) and \(P\) is:

• A. \(P
• B. \(Be
• C. \(P
• D. \(P

Hint:

Metallic character increases down a group and decreases from left to right across a period.

Answer 1

The Correct Option is A

Step 1: Understanding the Topic:
The question relates to "Classification of Elements and Periodicity in Properties." Metallic character (or electropositivity) is the tendency of an element to lose electrons and form cations. This property follows regular trends in the periodic table. Understanding these trends allows us to rank elements based on their reactivity and physical properties like electrical conductivity.
Step 2: Key Formulas and Approach:
The trends are:
Across a Period (left to right): Metallic character decreases due to an increase in effective nuclear charge, which makes it harder to remove valence electrons.
Down a Group: Metallic character increases as atomic size increases and shielding effect increases, making valence electrons easier to remove.

Step 3: Detailed Explanation:

Positions: Na, Mg, Si, P are all in Period 3. Be is in Period 2 (directly above Mg).
Period 3 Ranking: Na (Group 1) is most metallic, followed by Mg (Group 2), then the metalloid Si, and finally the non-metal P. (Order: $P<Si<Mg<Na$).
Group 2 Ranking: Since metallic character increases down a group, Mg (Period 3) is more metallic than Be (Period 2).
Refining the order: Phosphorus is a non-metal (lowest). Silicon is a metalloid. Between the metals Be, Mg, and Na:
Na is more metallic than Mg (Period trend).
Mg is more metallic than Be (Group trend).
Be is further to the right and higher up than Na/Mg, making it less metallic than them but more so than Si.

Final Order: $P<Si<Be<Mg<Na$.
Step 4: Final Answer:
The correct increasing order is option (A).