Part 4: The Group 16 Elements - General Properties

Front

What is the general valence-shell electronic configuration of Group 16 elements?

Back

ns2 np4 configuration in valence shell

Answer explanation

Group 16 elements, also known as the chalcogens, have the general valence-shell electronic configuration of ns2 np4. This configuration indicates they have six valence electrons, which is characteristic of this group.

Front

Why does oxygen commonly form the oxidation state of −II in compounds?

Back

It gains two electrons to reach noble gas.

Answer explanation

Oxygen commonly has an oxidation state of −II because it gains two electrons to achieve a stable electron configuration, resembling that of the nearest noble gas, neon.

Front

Down Group 16, the tendency to show metallic character:

Back

increases steadily from O to Po

Answer explanation

As we move down Group 16 from oxygen (O) to polonium (Po), the elements exhibit increasing metallic character due to the decrease in electronegativity and increase in atomic size, making 'increases steadily from O to Po' the correct choice.

Front

Which pair lists common higher oxidation states shown by S, Se, and Te?

Back

+IV and +VI states are common

Answer explanation

S, Se, and Te commonly exhibit +IV and +VI oxidation states due to their ability to expand their valence shell. The +IV state is typical in compounds like sulfates, while +VI is seen in compounds like selenates and tellurates.

Front

Why is oxygen less likely than sulfur to form multiple bonds using pπ–pπ overlap with heavier elements?

Back

No available d orbitals and small size.

Answer explanation

Oxygen's small size limits its ability to form multiple bonds through pπ–pπ overlap. Additionally, it has no available d orbitals, unlike heavier elements, which restricts its bonding capabilities.

Front

Which statement best describes the stability of O2− compared with S2− in aqueous solutions with increasing atomic size down the group?

Back

O2− is more stable; S2− is less stable

Answer explanation

O2− is more stable than S2− in aqueous solutions due to its smaller ionic size, which leads to stronger interactions with water molecules. As atomic size increases down the group, S2− becomes less stable compared to O2−.

Front

Which trend is observed for electronegativity within Group 16?

Back

Highest for O and decreases down group

Answer explanation

In Group 16, electronegativity is highest for oxygen (O) due to its small size and high effective nuclear charge. As you move down the group, the electronegativity decreases because of increasing atomic size and shielding effect.

Front

Which statement correctly contrasts oxygen with the rest of Group 16 regarding catenation and multiple bonding?

Back

Sulfur catenates more; oxygen forms stronger H-bonds

Answer explanation

Sulfur can catenate more effectively than oxygen due to its larger atomic size and lower electronegativity. Conversely, oxygen forms stronger hydrogen bonds due to its high electronegativity, making the correct contrast: 'Sulfur catenates more; oxygen forms stronger H-bonds'.

Front

Which reaction illustrates a method to reduce SO2 emissions from flue gases using calcium hydroxide?

Back

Ca(OH)2 + SO2 → CaSO3 + H2O

Answer explanation

The reaction Ca(OH)2 + SO2 → CaSO3 + H2O shows how calcium hydroxide can react with sulfur dioxide to form calcium sulfite and water, effectively reducing SO2 emissions from flue gases.

Front

How does atmospheric SO2 become an acid-forming species in air?

Back

Oxidation to SO3 then hydration to H2SO4

Answer explanation

SO2 is oxidized to SO3 in the atmosphere, which then reacts with water to form H2SO4, a strong acid. This process is the primary pathway for acid rain formation, making 'Oxidation to SO3 then hydration to H2SO4' the correct choice.