s-Block Elements (Alkali and Alkaline Earth Metals)

s-Block Elements (Alkali and Alkaline Earth Metals)NEET Chemistry · Class 11 · NCERT Chapter 11

Overview Notes NEET Questions Interactive Learning

2 interactive concept widgets for s-Block Elements (Alkali and Alkaline Earth Metals). Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.

On this page

Flame test colour identifier + quiz (8 elements)

Group 1 vs Group 2: property trends comparison table

Flame test colours

See the characteristic flame colours for 8 elements (Li, Na, K, Rb, Cs, Ca, Sr, Ba). Quiz mode tests your recall with 6 questions.

s-Block elements

Flame test simulator

Click each element to see its characteristic flame colour, wavelength, and notes. Then take a 6-question quiz to test your recall.

Click an element to see its flame colour, wavelength, and key notes.

Click an element above to see its flame colour.

Try this

Na gives the most intense yellow flame. Even tiny Na impurities in another salt can mask its true colour.
K gives lilac/violet — use cobalt blue glass to filter out the Na yellow and see K clearly.
Ba = green (apple green). Sr = scarlet. Ca = brick red. Li = crimson. Na = golden yellow.

Alkali vs alkaline earth metal comparison

Toggle between Group 1 and Group 2. Click any property row (atomic radius, IE, melting point, reactivity, flame colour) to read the trend explanation.

s-Block elements

Alkali and alkaline earth comparison

Side-by-side property table for Group 1 (Li to Cs) and Group 2 (Be to Ba). Click any property to see the trend direction and explanation.

Compare properties across Group 1 and Group 2 elements. Click any property header to see the trend explanation.

Lithium

Sodium

Potassium

Rubidium

Caesium

Atomic radius

152 pm (smallest)

186 pm

227 pm

248 pm

265 pm (largest G1)

IE₁

520 kJ/mol (highest in G1)

496 kJ/mol

419 kJ/mol

403 kJ/mol

376 kJ/mol (lowest G1)

Reaction with H₂O

Burns in water, less vigorous than Na

Vigorous, floats, catches fire

Very vigorous, lilac flame

Very vigorous

Explosive

Nature of oxide

Li₂O (normal oxide)

Na₂O (normal); Na₂O₂ in excess O₂

K₂O (normal); KO₂ (superoxide)

Rb₂O; RbO₂ (superoxide)

Cs₂O; CsO₂ (superoxide)

Hydroxide solubility

LiOH: slightly soluble

NaOH: highly soluble

KOH: highly soluble

RbOH: highly soluble

CsOH: highly soluble

Flame test colour

Crimson red

Golden yellow

Lilac/violet

Red-violet

Blue-violet

Click any property row to see the trend explanation.

Try this

Group 2 hydroxide solubility increases down the group (Be insoluble, Ba soluble) — opposite to Group 2 sulfate solubility (BaSO₄ is least soluble).
BeO and Be(OH)₂ are amphoteric — react with both HCl and NaOH. This makes Be similar to Al (diagonal relationship).
Alkali metals form different oxides with excess O₂: Li → Li₂O (normal), Na → Na₂O₂ (peroxide), K/Rb/Cs → KO₂ (superoxide).

Next chapter interactive widgets

Drag, slide and recompute on the next chapter's widgets.

Previous chapter

Class 11 · Ch 10

Hydrogen

Open interactive widgets

Next chapter

Class 11 · Ch 12

Some p-Block Elements

Open interactive widgets

Track Your NEET Score Across All 90 Chapters

Free 14-day trial. AI tutor, full mock tests and chapter analytics — built for NEET 2027.

Free 14-day trial · No credit card required