Question

An element having electronic configuration $\text{ 1}{{\text{s}}^{\text{2}}}\text{2}{{\text{s}}^{\text{2}}}\text{2}{{\text{p}}^{\text{6}}}\text{3}{{\text{s}}^{\text{2}}}\text{3}{{\text{p}}^{\text{6}}}\text{4}{{\text{s}}^{\text{1}}}\text{ }$forms?
A) Acidic oxide
B) Basic oxide
C) Amphoteric oxide
D) None

Answer 1

Hint: In the periodic table, group 1 elements have the general last shell electronic configuration$\text{ n }{{\text{s}}^{\text{1}}}\text{ }$. They are reactive metals and readily reacts with the oxygen to form the corresponding mono oxides with formula as $\text{ }{{\text{M}}_{\text{2}}}\text{O }$or can form the superoxide or peroxides. The metal oxides undergo the neutralization reaction in an aqueous solution to form salt and water.

Complete step by step solution:
Group 1 (alkali earth metal) has the one valence electron in the outermost shell. The outer orbital –s orbitals occupy the valence electron which is spherical. On ignoring the inner shell the general electronic configuration of the alkali earth metal is written as$\text{ n }{{\text{s}}^{\text{1}}}\text{ }$.
Group 1 elements are reactive; they exhibit metallic properties.as they have one electron in the outer shell, they readily lose their electron to electronegative elements and form ionic bonds.
They are reactive towards the oxygen atom and form the corresponding oxides. The metal oxides are crystalline solid which metal is a cation and oxide is an anion. Alkali metal can lose its one electron thus have $\text{ +1 }$ oxidation state and forms oxides of the general formula $\text{ }{{\text{M}}_{\text{2}}}\text{O }$.
Metal oxides of alkali earth metal react with water and form the basic solution of neutral hydroxide as
$\text{ }{{\text{M}}_{\text{2}}}\text{O + }{{\text{H}}_{\text{2}}}\text{O }\to \text{ 2MOH }$
Thus oxides of alkali earth metal are called basic oxides.
We have given an element which has the electronic configuration as the $\text{ 1}{{\text{s}}^{\text{2}}}\text{2}{{\text{s}}^{\text{2}}}\text{2}{{\text{p}}^{\text{6}}}\text{3}{{\text{s}}^{\text{2}}}\text{3}{{\text{p}}^{\text{6}}}\text{4}{{\text{s}}^{\text{1}}}\text{ }$. The given elements have the $\text{ 4s }$ as the outer orbital. It holds a single electron in it. It satisfied the general last shell configuration of the alkali earth metals. Thus the given element is alkali earth metal.it has 19 electrons. The element is potassium K.
The potassium forms potassium oxide $\text{ }{{\text{K}}_{\text{2}}}\text{O }$ . This reaction with water forms a potassium hydroxide which is known as the strong base.
$\text{ }{{\text{K}}_{\text{2}}}\text{O + }{{\text{H}}_{\text{2}}}\text{O }\to \text{ 2}{{\text{K}}^{\text{+}}}\text{O}{{\text{H}}^{-}}\text{ }$ 

$\text{ KOH }$ is used in the neutralization reaction to neutralize the acid.
Thus, the given alkali earth metal K forms a basic oxide.

Hence, (B) is the correct option.

Note: The metal can form three types of oxides viz monoxide, superoxide and peroxide. The alkali metals form all of them. Like group 1 elements, group 2 (alkaline earth metal) also forms the metal oxides $\text{ MO }$. This is basic for example $\text{ CaO }$, $\text{ MgO }$. Remember that, the basicity of oxides decreases as we move from left to right in the periodic table and the acidity of oxides increases. The non-metals (measuredly located in p-block) have acidic oxides. Hydrogen forms an amphoteric oxide $\text{ }{{\text{H}}_{\text{2}}}\text{O }$.