Arrange these in the increasing order of Metallic character: → B, Al, Mg, K

Question

Accepted Answer

The correct option is (2):

Metallic character refers to the tendency of an element to lose electrons and form positive ions (cations). This property generally increases down a group and decreases across a period from left to right in the periodic table. Let's consider the elements provided: Boron (B), Aluminum (Al), Magnesium (Mg), and Potassium (K).  * Potassium (K) is an alkali metal in Group 1, Period 4. It has only one valence electron and a large atomic size, making it very easy to lose this electron. Thus, K exhibits the highest metallic character among these elements.
  * Magnesium (Mg) is an alkaline earth metal in Group 2, Period 3. It is less metallic than K because it is in a different group (further to the right) and in an earlier period. While it tends to lose two electrons, it holds them more strongly than K.
  * Aluminum (Al) is in Group 13, Period 3. It is a post-transition metal, but its metallic character is significantly less than Mg because it is further to the right in the same period. This means its effective nuclear charge is higher, holding its valence electrons more tightly.
  * Boron (B) is in Group 13, Period 2. It is classified as a metalloid, exhibiting properties of both metals and nonmetals, but predominantly non-metallic character compared to Al, Mg, and K. It has a small atomic size and a relatively high effective nuclear charge, making it difficult to lose electrons.Therefore, arranging them in increasing order of metallic character, we get B < Al < Mg < K.

The incorrect option is (1): K\<Mg\< Al\<B. This option incorrectly places K as the least metallic and B as the most metallic, which contradicts the general trends of metallic character in the periodic table.
The incorrect option is (3): Mg\<K\<B\<Al. This option is incorrect because it misrepresents the metallic character order, particularly by placing Mg before K and Al before B, going against the periodic trends.
The incorrect option is (4): Al \<B\< Mg \< K. This option incorrectly orders B and Al, as Al has a greater metallic character than B due to being in a higher period.