The correct decreasing order for metallic character is

We need to find the correct decreasing order of metallic character for the elements Na, Mg, Be, Si, and P.

Metallic character depends on how easily an atom can lose electrons. It increases as we go down a group (larger atomic size, easier to lose outer electrons) and decreases as we go from left to right across a period (increasing nuclear charge holds electrons more tightly).

Let us identify the positions of these elements in the periodic table. Na (sodium) is in Group 1, Period 3. Mg (magnesium) is in Group 2, Period 3. Be (beryllium) is in Group 2, Period 2. Si (silicon) is in Group 14, Period 3. P (phosphorus) is in Group 15, Period 3.

Among the Period 3 elements, the metallic character decreases from left to right: $$Na > Mg > Si > P$$. Now, Be is in the same group as Mg but in a higher period (Period 2), so Be is less metallic than Mg (since metallic character increases going down the group).

Comparing Be with Si and P: Be is in Group 2 (a metal), while Si is a metalloid and P is a non-metal. So Be is more metallic than both Si and P.

Putting it all together, the decreasing order of metallic character is $$Na > Mg > Be > Si > P$$.

Hence, the correct answer is Option A.