Yes, cuz formation of some compounds is not spontaneous-- they absorb energy and, hence, del.H is positive - spontaneous, release energy- delta h negative

Favourable conditions for formation of ionic compound

Del f H should be negative- i.e- BDE, SE IE should be low- as they are positive values and, L.E , del. eg H -- high

Ionic solids are... (color) (state)

White, crystalline solid

Do ionic compounds show isomerism, why?

No, they are non directional

Why IC have high mp and bp

Strong forces of attraction

Why are ic brittle?

When one layer slides over other- same type of chrges over each other- repulsion- breaks

IC are more soluble in solvents having ... dielectric constants

HIGH

Meaning of dielectric constant

Solvent ne dissolving compound ke electrostatic force of attraction ko E times weak kar diya

Process of hydration

Solvation in water

Sharing of electrons- covalent bond formed between

Two electropositive elements

Hypovalent species vs hypervalent species

Sharing ke baad 8 e se kam vs. sharing ke baad 8 e se jyada

Instances of failure of law of octet

1. H 2. hypo and hypervalent 3. odd e- mol. 4. inert gases forming compounds

Concepts (2) in valence bond theory

Concept of overlapping concept of hybridization

Concept of overlapping

Based on energy minimization tendency of a system- not octet

Benefit of overlapping

E- cloud do nucleus ke command mein hain - attraction increases - energy further decreases therefore bond more stable

Overlapping continues till

A sweet spot of maximum energy is reached

Axial vs collateral overlapping in s-s vs p-p

Axial- internuclear axis ke along collateral- internuclear axis ke upar neeche

Covalent molecule- only ... filled molecules overlap

Half filled

Overlapping orbitals should have... symmetry

Same symmetry ++ or -- not +- ....apavitra rishta SUM 0

FAILURE OF overlapping

Failed to explain poluatomic molecules like- CH4 - all symmetrical even though one 2s1s and other three 2p1s - all bond angle and bond length same(shouldnt be acc to overlapping)

Launch of hybridisation

Redistribution of energy- hybrid orbitals- to explain polyatomic mol. - poly at mol- hybridisation ke baad hi overlap hota hai

Hybridisation defn

When orbitals of diff energies intermix and redistribute their energies to form orbitals of similar energy its called hybridisation and new orbitals - hybrid orbitals

Type of hyb.=

No of surrounding atoms + no of lone pairs on the central atom

....bonds are longer and weaker than ....bonds

Axial weaker than equitorial

,....(a/e) feel more repn and whY?

Each eq. bond is repelled by three axial bonds while each axial bond is repelled by three equitorial bonds - axial bonds feel more repn. - BS dec, and BL inc

In case of sp3d- lone pairs are always plced at...a/e

Equitorial positon

BP- BP vs LP BP vs LP LP repn comparision - vsepr explains

<< - bond angle and shape of molecules

LP should always be placed at a/e

Equitorial

In ether bond(ROR) angle b/n two R-R groups is... and why

110 deg greater than b/w two lp cuz of steric hindrance same with ncl3 and NBr3

Pi bond should be kept on ...(a/e)

Equitorial to minimize pi-pi or sigma-pi repulsion

Why SiO2 has different structure from CO2

Sp3 in SiO2 vs sp in CO2 cuz co2 small discrete molecule while silica a giant lattice