Periodic Trends — Set 1

Correct Answer: B. Fluorine

• **Fluorine supremacy** = Fluorine has the highest electronegativity at 4.0 on the Pauling scale of all elements. • **Strongest attraction** — Its smaller size and higher nuclear charge make it strongest electron attractor. • 💡 Wrong-option analysis: A: Chlorine is 3.0; C: Oxygen is 3.4; D: Nitrogen is 3.0.

Correct Answer: B. It decreases

• **Radius decrease** = Atomic radius decreases across a period due to increasing nuclear charge. • **Stronger pull** — Same electron shell experiences greater attraction from increasing protons. • 💡 Wrong-option analysis: A: Electrons don't increase in size; C: No such pattern exists; D: Radius significantly changes.

Correct Answer: D. Group 16

• **Group 16 elements** = Group 16 elements are collectively referred to as the Chalcogens (ore-forming elements). • **Includes oxygen** — Oxygen, sulfur, selenium, tellurium, and polonium comprise this group. • 💡 Wrong-option analysis: A: Group 17 are halogens; B: Group 15 are pnictogens; C: Group 18 are noble gases.

Correct Answer: C. Francium

• **Francium reactivity** = Francium is the most metallic element as it loses its valence electron most easily. • **Extreme reactivity** — It's so reactive it's rarely found and quickly decays radioactively. • 💡 Wrong-option analysis: A: Cesium is highly metallic but less than francium; B: Sodium is less reactive; D: Potassium is less reactive.

Correct Answer: C. Groups

• **Groups definition** = Vertical columns are known as groups (or families) containing 18 standard groups. • **Similar properties** — Elements in the same group have similar chemical properties and valence electrons. • 💡 Wrong-option analysis: A: Periods are horizontal rows; B: Series is outdated terminology; D: Blocks are orbital categories.

Correct Answer: B. Chlorine

• **Chlorine advantage** = Chlorine has higher electron affinity than fluorine despite smaller size. • **Optimal size** — Chlorine's larger size compared to fluorine provides better orbital overlap. • 💡 Wrong-option analysis: A: Iodine has lower affinity; C: Bromine has lower affinity; D: Fluorine has anomalous lower value.

Correct Answer: C. Group

• **Group arrangement** = Elements in the same group have the same number of valence electrons and similar chemistry. • **Predictable behavior** — This organization allows prediction of element properties based on group membership. • 💡 Wrong-option analysis: A: Periods have different properties; B: Blocks are orbital descriptions; D: Row is same as period.

Correct Answer: A. Electron Affinity

• **Electron affinity measure** = Electron affinity measures energy released when a neutral atom gains an electron. • **Exothermic process** — More negative values indicate stronger preference for gaining electrons. • 💡 Wrong-option analysis: B: Ionization is electron removal; C: Electronegativity is relative property; D: Lattice is ionic compound energy.

Correct Answer: B. Periods

• **Periods definition** = Horizontal rows called periods represent number of electron shells (7 total). • **Filling pattern** — Each period corresponds to filling a new electron shell with electrons. • 💡 Wrong-option analysis: A: Groups are vertical columns; C: Blocks relate to orbital types; D: Families is outdated for groups.

Correct Answer: C. Helium

• **Helium ionization** = Helium has the highest ionization energy as electrons closest to nucleus. • **Smallest atom** — Its small size results in extremely strong nuclear attraction on electrons. • 💡 Wrong-option analysis: A: Neon is second highest; B: Argon is lower than neon; D: Hydrogen is much lower.