The electronic configuration of an element is 2,8,2. The hydroxide of this element can produce ______ hydroxyl ions per molecule.
Show Hint
- 3
- 2
- 1
- 4
The Correct Option is B
Solution and Explanation
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.
Top Questions on Periodic Table
Which of the following element pairs will form an ionic bond?
- ICSE Class X board - 2026
- Chemistry
- Periodic Table
- An atom of X forms an ion according to the equation ( X + 2e^- X^2- ). The atomic number of the atom X is:
- ICSE Class X board - 2026
- Chemistry
- Periodic Table
- Element A belongs to group 15 and period 2 of the Periodic Table.
(a) Identify the element A.
(b) Write the formula of the compound formed when element A combines with hydrogen.
(c) Draw the dot (●) and cross (×) structure of the compound formed in (b) above.
- ICSE Class X board - 2026
- Chemistry
- Periodic Table
State whether the following statements are True or False.
(a) Organic compounds having different molecular formula, but same structural formula are called isomers.
(b) A salt is a compound formed by partial or complete replacement of the hydrogen ion of an acid by a metal or electropositive ion.
- ICSE Class X board - 2026
- Chemistry
- Periodic Table
Anil is a laboratory assistant in a college. He prepared nitric acid but stored it in a transparent container exposed to sunlight. After a few days, brown fumes were observed in the container and the acid turned slightly yellowish in colour.
(a) What was the error made by Anil while storing the acid?
(b) Why were brown fumes observed in the container?
(c) How can the yellowish tinge in the acid be removed?
- ICSE Class X board - 2026
- Chemistry
- Periodic Table
Questions Asked in ICSE Class X board exam
- (a) Name the electromagnetic radiation used to detect fake currency.
(b) Redraw the diagram given below and complete the path of the light ray AB through the glass prism till it emerges out of the prism. Critical angle of the glass is 42\(^\circ\).
- ICSE Class X board - 2026
- Refraction of Light
- A monochromatic ray strikes the surface of identical prisms (A, B and C) at different angles of incidence. The diagram below shows their refracted rays. Study the path of these refracted rays and identify in which of the diagrams
(a) the angle of incidence is maximum.
(b) the angle of incidence is minimum.
(c) the angle of incidence is equal to the angle of emergence.
- ICSE Class X board - 2026
- Refraction of Light
- For a body to be in dynamic equilibrium, its:
- ICSE Class X board - 2026
- laws of motion
Given below is the industrial process for the manufacture of ammonia gas. Study the schematic diagram to answer the following questions.
(a) Name the process.
(b) Which catalyst is used in the above process?
(c) In the above diagrammatic setup, how is ammonia gas separated from the unreacted gases to obtain liquid ammonia?
(d) Which two properties of ammonia gas can be demonstrated by the Fountain Experiment?
- ICSE Class X board - 2026
- Occurrence Of Metals
(a) Give the IUPAC name for the following organic compounds:
- ICSE Class X board - 2026
- Organic Chemistry