Free s-Block and p-Block Elements MCQs with Answers

• A. Tincal
• B. Boric acid
• C. Calcium carbonate
• D. Colemanite

Explanation: Tincal, or natural borax, occurs in evaporite deposits and dried-up lake beds, including those of Tibet and California.

• A. Soil porocity
• B. Proper growth of plants
• C. Alkalinity of soil
• D. All

Explanation: Boron is required only in small quantities, but it is essential for proper plant growth, including cell-wall formation and reproductive…

• A. decrease
• B. increase
• C. remains constant
• D. first decreases then increases

Explanation: Gallium arsenide is a semiconductor, and increasing temperature supplies more energy for electrons to cross the band gap into the…

• A. metal borate
• B. metal meta borate
• C. metal boride
• D. metal silicate

Explanation: In the borax bead test, borax forms a glassy boron oxide medium that reacts with a metal oxide to produce a coloured metal metaborate.

• A. it has small size
• B. it has high nuclear charge
• C. it forms molecular addition compounds
• D. all of the above

Explanation: Boron has a very small atomic size, high ionisation energy and high charge density, so it forms mainly covalent molecular compounds rather…

• A. As nitrometer
• B. To remove air bubbles from molten metal
• C. To produce alloy
• D. As insulator

Explanation: Aluminium has a strong affinity for both oxygen and nitrogen, so it reacts with dissolved gases in molten metal and helps remove air…

• A. 26%
• B. 27%
• C. 37%
• D. <2.6%

Explanation: The solubility of orthoboric acid rises sharply with temperature, reaching about 37% at 107°C, compared with 2.6% at 40°C.

• A. Small size
• B. High nuclear charge
• C. Both A and B
• D. No authorized justification yet

Explanation: Boron has a very small atomic size and a high effective nuclear attraction for its valence electrons, giving it high ionisation energy and…

• A. high first ionization potential
• B. high second ioniation potential
• C. high ionic radius
• D. high electronegativity

Explanation: After losing one electron, sodium has the stable noble-gas configuration of neon.

• A. Sodium and Lithium
• B. Lithium and magnesium
• C. Lithium and beryllium
• D. Boron and Beryllium

Explanation: Lithium and magnesium lie diagonally opposite each other in the periodic table and show similar properties, such as forming nitrides and…

• A. They are more reactive
• B. They have greater atomic radii
• C. They have smaller atomic sizes
• D. All

Explanation: Alkaline-earth atoms have two valence electrons and generally smaller atomic sizes than the corresponding alkali metals in the same…

• A. Ca
• B. Cr
• C. Both of the above
• D. None of the above

Explanation: Cesium is an alkali metal and does not have the characteristic diagonal relationship with calcium or chromium; its closest group…

• A. Mg > Sr
• B. Ba > Mg
• C. Lu > Ce
• D. C1 > I

Explanation: Atomic size generally increases down a group because extra electron shells are added, so barium is larger than magnesium.

• A. Increase down the group
• B. Decrease down the group
• C. No regular trend
• D. Remain same

Explanation: Metallic character increases down Group 1 because atomic size and shielding increase, making the outer electron easier to remove.

• A. Exothermic
• B. Endothermic
• C. Data is insufficient
• D. Unpredictable

Explanation: Adding a second electron to a uninegative ion is endothermic because the incoming electron is repelled by the already negative ion, so…

• A. Nuclear charge
• B. Atomic size
• C. Shielding effect
• D. I.E depends upon all of the above and nature of orbital

Explanation: Ionization energy depends on nuclear charge, atomic size, shielding, and the type of orbital from which the electron is removed, so all…

• A. Ionization energy
• B. Atomic radii
• C. Melting & boiling points
• D. Atomic volume

Explanation: Across a period, melting and boiling points generally rise as stronger metallic or covalent network bonding develops, reaching a maximum…

• A. Location of nucleus by Rutherford
• B. Atomic number by Moseley
• C. X-rays by Roentgen
• D. Natural radioactivity by Henry Bacquerel.

Explanation: Moseley showed that elements should be arranged by increasing atomic number rather than atomic mass, leading to the modern periodic law…

• A. Melting point of elements
• B. Boiling point of elements
• C. Ionization energy of elements
• D. Coordination number of ions

Explanation: Melting point, boiling point, and ionization energy show systematic variation with atomic number and are therefore periodic properties.

• A. Boron & Beryllium
• B. Nitrogen & Phosphorous
• C. Magnesium & Aluminium
• D. Gallium & Helium

Explanation: Nitrogen and phosphorus are both in Group 15, with five valence electrons and similar chemical behaviour.