Question

Which of the following is most acidic in nature?
A.BeO
B.MgO
C.CaO
D.BaO

Answer 1

All the given oxides belong to the second group of periodic tables. And we also know that moving down the group metallic character increases and Electronegativity decreases down the group. Now try to relate these properties to come up with the correct solution.

Complete step by step answer:
Electronegativity: It measures the pull of an atom of a component on the electrons during a bond (covalent). The stronger its pulling power the upper its electronegativity. Electronegativity increases from left to right across a period. because the nuclear charge increases from one element to subsequent across the amount the additional electrons enter to an equivalent shell. Thus there is, in effect, a greater pull on electrons which are an equivalent distance away. Electronegativity decreases down a group. As a group is descended the outer shell of electrons gets beyond the positive nucleus therefore the pull on these electrons gets less from one element to subsequent. The foremost electronegative element is fluorine(F), followed by oxygen(O).

The Group 2 alkaline-earth metal metals include Beryllium, Magnesium, Calcium, Barium, Strontium and Radium and are soft, silver metals that are less metallic in character than the Group 1 Alkali Metals. Although many characteristics are common throughout the group, the heavier metals like Ca, Sr, Ba, and Ra are almost as reactive because the Group 1 Alkali Metals. All the weather in Group 2 has two electrons in their valence shells, giving them an oxidation number of +2.
In metals moving down the group metallic character increases, so basic nature increases hence most acidic are going to be BeO as Be is least metallic in group 2 elements.
BeO is most acidic in nature because the acidity of oxides decreases with increases within the electropositive character of the central atom.
Thus, the correct option is A.

Note:
As for any group within the table the Group 2 atoms get larger. So do their ions. The ions have a charge of +2 when the atoms lose the 2 outermost-level electrons, leaving this level empty. The 2 electrons of the $Be^{2+}$ ion occupy the primary energy state only therefore the ion is extremely small. Ions like this, small and highly charged, have a high charge density and therefore the charge density of the $Be^{2+}$ ion is extremely high indeed. Due to this the properties of beryllium and its compounds aren't typical of the opposite Group 2 elements.