Introduction to s-Block and p-Block Elements

• Elements are classified based on the block of the periodic table they occupy, determined by the type of atomic orbital being filled.

• s-Block: Groups 1 (Alkali Metals) & 2 (Alkaline Earth Metals), outermost electrons in s-orbital.

• p-Block: Groups 13–18, outermost electrons in p-orbital.

• NEET emphasizes conceptual trends, reactivity, and periodic properties rather than memorization.

Key Concept: The chemical behavior of an element is mainly determined by its valence electrons.

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s-Block Elements

Alkali Metals (Group 1: Li, Na, K, Rb, Cs, Fr)

Properties:

• Soft, low density, metallic luster

• Highly reactive, especially with water → form hydroxides and hydrogen

• Good reducing agents

Trends:

• Reactivity increases down the group

• Atomic radius increases; ionization energy decreases

• Form ionic compounds

Conceptual Focus: Understand reactivity with water, halogens, and oxygen, and how reactivity relates to low ionization energy.

Alkaline Earth Metals (Group 2: Be, Mg, Ca, Sr, Ba, Ra)

Properties:

• Harder than alkali metals

• Less reactive than alkali metals

• Form oxides and hydroxides; basic in nature

Trends:

• Reactivity increases down the group

• Atomic radius increases; ionization energy decreases

• Oxides and hydroxides become more basic down the group

NEET Tip: Focus on solubility and basicity trends, important for application-based questions.

p-Block Elements

Group 13 Elements (B, Al, Ga, In, Tl)

Properties:

• Tri-valent elements

• Boron: metalloid; others: metals

• Form covalent compounds with non-metals

Trends:

• Metallic character increases down the group

• Oxides become more basic down the group

• Reactivity: Al is highly reactive due to oxide layer

NEET Focus: Link valency, reactivity, and metallic character conceptually.

Group 14 Elements (C, Si, Ge, Sn, Pb)

Properties:

• Tetravalent

• C and Si: non-metals; Sn and Pb: metals

• Form oxides and hydrides (CH₄, SiH₄)

Trends:

• Metallic character increases down the group

• Oxides: C and Si form acidic oxides; Sn and Pb form amphoteric oxides

Conceptual Focus: Understand catenation (C > Si > Ge) and bonding trends in group 14.

Group 15 Elements (N, P, As, Sb, Bi)

Properties:

• Pentavalent, but show +3 and +5 oxidation states

• N and P: non-metals; As and Sb: metalloids; Bi: metal

• Nitrogen forms strong triple bond (N₂) → less reactive

Trends:

• Metallic character increases down the group

• Oxidation states: +5 dominates for light elements; +3 for heavier elements due to inert pair effect

NEET Tip: Conceptually relate oxidation states to stability and inert pair effect.

Group 16 Elements (O, S, Se, Te, Po)

Properties:

• Chalcogens

• Form acidic oxides (O₂, S) and amphoteric oxides (Te, Po)

• Usually show -2 oxidation state

Trends:

• Metallic character increases down the group

• Electronegativity decreases down the group

Conceptual Focus: Link oxidation states and acid-base character.

Group 17 Elements (F, Cl, Br, I, At)

Properties:

• Halogens; highly reactive non-metals

• Form diatomic molecules (F₂, Cl₂)

• React with metals to form halides

Trends:

• Reactivity decreases down the group

• Electronegativity decreases

• Oxidizing power decreases

NEET Tip: Focus on reactivity with metals, halide formation, and oxidizing trends.

Group 18 Elements (He, Ne, Ar, Kr, Xe, Rn)

Properties:

• Noble gases; inert due to stable electronic configuration

• Monatomic gases

• Very low chemical reactivity

Trends:

• Density increases down the group

• Melting and boiling points increase

Conceptual Focus: Conceptual understanding of why noble gases are chemically inert and their industrial uses.

Conceptual Summary Table

Conclusion

The s-Block and p-Block Elements chapter is critical for NEET Chemistry, covering periodic trends, reactivity, metallic/non-metallic character, oxidation states, and properties. Conceptual understanding is crucial:

• s-Block → highly reactive metals, reducing agents

• p-Block → diverse properties, varying oxidation states, acidic/basic oxides

• Group-wise trends help in predicting chemical behavior and reactivity.

StudentBro.in provides structured, fully conceptual notes to help NEET aspirants understand and remember trends efficiently, with H4 bold headings for readability and SEO.