Question

The electronic configuration of an element is 2,8,2. The hydroxide of this element can produce ______ hydroxyl ions per molecule.

• A. 3
• B. 2
• C. 1
• D. 4

Hint:

The number of ionizable OH^- ions in a base is known as its acidity. Therefore, Magnesium hydroxide is a diacidic base.

Answer 1

The Correct Option is B

Step 1: Identifying the Element: 
The total number of electrons is 2 + 8 + 2 = 12. The element with atomic number 12 is Magnesium (Mg). 

Step 2: Determining Valency: 
Magnesium has 2 electrons in its outermost shell. To achieve stability, it loses these 2 electrons to form a divalent cation, Mg^2+. 

Step 3: Writing the Hydroxide Formula: 
Hydroxide is a radical with a valency of 1 (OH^-). To balance the Mg^2+ ion, two OH^- ions are required. The chemical formula is Mg(OH)_2. 

Step 4: Final Answer: 
Upon dissociation, one molecule of Mg(OH)_2 produces 2 hydroxyl ions.