Free Periodic Properties and Trends MCQs with Answers

• A. decreases, because nuclear charge increases while electrons enter the same shell
• B. increases, because more electrons are added
• C. stays the same
• D. increases, because the nuclear charge decreases

Explanation: Each successive element adds one proton and one electron, but the electron enters the same outermost shell, so shielding hardly changes…

• A. add one electron to a gaseous atom
• B. remove one mole of electrons from one mole of gaseous atoms, forming gaseous unipositive ions
• C. break one mole of covalent bonds
• D. convert one mole of a solid into a gas

Explanation: The definition specifies the gaseous state so that no lattice or intermolecular forces interfere, and it is always endothermic because an…

• A. Oxygen
• B. Chlorine
• C. Fluorine
• D. Nitrogen

Explanation: Fluorine is the most electronegative element on the Pauling scale at 4.0, because it is small and has a high effective nuclear charge, so…

• A. decreases, because atomic size increases
• B. increases, because the atoms get smaller and the nuclear charge increases
• C. remains constant
• D. decreases, because shielding increases sharply

Explanation: A greater nuclear charge acting on a shell at nearly constant distance holds the outer electrons more tightly, so more energy is needed to…

• A. acidic through amphoteric to basic
• B. acidic to neutral only
• C. basic through amphoteric to acidic
• D. neutral to basic

Explanation: Sodium and magnesium oxides are basic, aluminium oxide is amphoteric and reacts with both acids and alkalis, and the oxides of phosphorus…

• A. sodium
• B. magnesium
• C. beryllium
• D. aluminium

Explanation: Lithium resembles magnesium because their ions have similar size to charge ratios, so both form nitrides directly with nitrogen, both give…

• A. Li
• B. Al
• C. Ca
• D. Ba

Explanation: Ionisation energy falls down a group as the outer electron lies further from the nucleus and is better shielded, and barium is the lowest…

• A. Cl
• B. F
• C. N
• D. Br

Explanation: Group VIIA, or group 17, contains the halogens fluorine, chlorine and bromine.

• A. P
• B. K
• C. Po
• D. Pt

Explanation: Potassium has the symbol K, derived from its Latin name kalium, rather than a symbol based directly on the English name.

• A. increase
• B. decrease
• C. constant
• D. none of these

Explanation: Across a period from left to right, effective nuclear charge generally increases while atomic radius decreases, so the attraction between…

• A. 35.5
• B. 17
• C. 15
• D. 21

Explanation: The atomic number, Z, equals the number of protons in an atom. Chlorine has 17 protons, so Z = 17; 35.5 is its approximate relative atomic…

• A. Au
• B. Ag
• C. Sv
• D. At

Explanation: Silver has the symbol Ag, derived from its Latin name argentum. Au is gold, while Sv is not an accepted chemical symbol, making Au the…

• A. Helium
• B. Hydrogen
• C. Chlorine
• D. Carbon

Explanation: Hydrogen makes up approximately 70% of the universe by mass because it was formed abundantly in the early universe and is the main element…

• A. Increases
• B. Decreases
• C. Remains Same
• D. None of them

Explanation: Across a period, added electrons enter the same principal shell, so the shielding effect remains nearly constant while nuclear charge…

• A. Protium
• B. Deuterium
• C. Tritium
• D. Nichromium

Explanation: Tritium, 3H, contains one proton and two neutrons and is radioactive because its nucleus is unstable.

• A. Copper sulphate
• B. Barium sulphate
• C. Cobalt sulphate
• D. Nickel sulphate

Explanation: The borax bead test gives characteristic colours mainly with transition-metal ions, such as copper, cobalt and nickel.

• A. 2.8
• B. 2.2
• C. 3.1
• D. 1.8Chemistry

Explanation: On the Pauling scale, hydrogen has an electronegativity of about 2.2, reflecting its moderate attraction for shared bonding electrons.

• A. 50%
• B. 60%
• C. 70%
• D. 80%

Explanation: Hydrogen constitutes roughly 70 to 75% of the universe by mass, especially when the composition of stars is considered, so 70% is the…

• A. All the metals are good conductor of electricity
• B. All the metals are good conductor of heat
• C. All the metals form positive ions
• D. All the metals form acidic oxides

Explanation: Metal oxides are not all acidic: many are basic, and some such as aluminium oxide are amphoteric.

• A. size of Cl atoms > Cl- ion
• B. size of Na+ ion < Na atom
• C. size of Na atom < Na+ ion
• D. Cl- < Na+

Explanation: A sodium atom loses its outer electron to form Na+, so the ion has fewer electron shells and a smaller radius: Na+ is smaller than Na.