MOLECULAR ORBITAL THEORY SIMPLIFIED

TOTAL NUMBER OF ELECTRONS:

10 11 12 13 14 15 16 17 18

1 1.5 2 2.5 3 2.5 2 1.5 1 <--- BOND ORDER

D P P P D P P P D

D ----> Dimagnetic

P------> Paramagnetic

the bond order calculated by the formula will always give you the correct answer.

but as for the magnetic nature...90% will be correct....

their are some exceptions like B2

both are paramagnetic

Inorganic 4 ALL ORES from METALLURGY(SIMPLIFIED)

SOME IMPORTANT METALS AND THEIR ORES:

1. SODIUM (Na):

Sodium Chloride NaCl (rock salt, table salt, common salt)

Sodium Carbonate Na₂CO₃ (Soda Ash)

Na₂CO₃.10H₂O(Washing Soda)

Na₂CO₃.H₂O(Crystal Carbonate)

Sodium Nitrate NaNO₃(chlie salt petre or chile nitre)

Borax Na₂B₄O₇.10H₂O(Tincal)

Sodium Sulphate Na₂SO₄.10H₂O(Glauber's Salt)

Cryolite Na₃AlF₆

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2.Potassium:

Potassium Chloride KCl(Sylvine)

Potassium Carbonate K₂CO₃(Pearl Ash)

Potassium Nitrate KNO₃(Indian Salt Petre,nitre or salt petre)

Carnallite KCl.MgCl₂.6H₂O

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3. Copper:

Cuprite Cu₂O (Ruby Copper)

Copper glance Cu₂S (Chalcocite)

Chalcopyrite CuFeS₂ or Cu₂S.Fe₂S₃(Copper pyrites)

Malachite CuCO₃.Cu(OH)₂

Azurite 2CuCO₃.Cu(OH)₂

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4.SIVER:

Native Silver Ag

Argentite Ag₂S

Horn silver AgCl (Kerargyrite)

Pyragyrite Ag₂S.Sb₂S₃(Ruby Silver)

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5. GOLD:

Native Gold Au

Sylvanite A telluride of Gold and Silver

Bismuth Auride AuBi

Calaverite AuTe₂

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6.MAGNESIUM:

Magnesite MgCO₃

Dolomite MgCO₃.CaCO₃

Carnallite KCl.MgCl₂.6H₂O

Epsom salt MgSO₄.7H₂O

Brucite Mg(OH)₂

Kieserite MgSO₄.H₂O

Schonite K₂SO₄.MgSO₄.6H₂O

Asbestos CaSiO₃.3MgSiO₃

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7.CALCIUM:

Limestone CaCO₃(iceland spar, marble, chalk, calcite)

Gypsom CaSO₄.2H₂O

Anhydrite CaSO₄

Flouride CaF₂(Flourspar)

Phosphite Ca₃(PO₄)₂

Chlorapatite 3Ca₃(PO₄)₂ .CaCl₂

Fluor apatite 3Ca₃(PO₄)₂ .CaF₂

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8. STRONTIUM:

Strontianite SrCO₃

Celestine SrSO₄

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9.BARIUM:

Witherite BaCO₃

Heavy spar BaSO₄

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10.ZINC:

Zincite ZnO

Calamine ZnCO₃

Zinc Blende ZnS (Black Jack)

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11. CADMIUM:

Greenokite CdS

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12. MERCURY:

Cinnabar HgS

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13. ALUMINIUM:

Corundum Al₂O₃

Diaspore Al₂O_3.H₂O

Bauxite Al₂O_3.2H₂O

Alunite K₂SO₄.Al₂(SO₄)₃.4Al(OH)₃ (Alum stone)

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14. TIN:

Cassiterite SnO₂

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15. LEAD:

Galena PbS

Cerrusite PbCO₃

Matlockite PbCl₂

Anglesite PbSO₄

Lanarkite PbO.PbSO₄

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16. IRON:

Haemitite Fe₂O₃

Load Stone Fe₃O₄

Limonite 2Fe₂O₃.3H₂O

Siderite FeCO₃(Spathic iron ore)

Iron Pyrites FeS₂

Chalcopyrite CuFeS₂

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17.MANGANESE:

Pyrolusite MnO₂

Braunite Mn₂O₃

Hausmannite Mn₃O₄

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18. TITANIUM:

Rutile TiO₂

Illmenite FeTiO₃

important things usually left in inorganic.

SECONDARY FORCES:

These forces decide the physical properties of the molecule like boiling point, meltiing point, refractive index, viscoscity and solubility

1. HYDROGEN BOND:

it is a type of dipole dipole interaction...

it is only shown by N, O , F

to learn it...

hydrogen ne FON (phone) lagaya to H-bonding hui.

NOTE: boiling point of water is greater than HF and NH3 exceptionally.

Q. Enthalpy of vapourization of H2O is greater than HF. WHY?

A. water evaporates as a monomer so we have to break all the H bonds but HF evaporates in the form of a dimer so we have to break less bonds.

(draw the diagram...it'll be clear to you at once)

2.INTRA MOLECULAR HYDROGEN BOND:

It is the hydrogen bond formed within the molecule:

example o-nitrophenol

meta and para isomers don't form intermolecular H-bond.

APPLICATIONS:

1. Boiling Point inter molecular H-bond

1/ intramolecular H bond Solubility

3. VISCOSCITY No. of H bonds Molecular weight

4. ACIDIC NATURE less H-bonds

Q.Paranitrophenol is more acidic than orthonitrophenol?

A. in orthonitrophenol due to intramolecular H-bonding a strong cyclic ring caleed as chelate is formd which provides extra stability to the molecule.

To phir khud hi soch lo wo apna H kyun dega.

kyunki agar usne H de diya to chelate ring toot jayegi.

1st disassociation of maleic acid is grtr dn fumaric acid because it acquires stability due to the chelate formation but the 2nd disassociation of maleic acid is less dn the fumaric acid

ALCOHOLS ARE SOLUBLE IN WATER DUE TO H-BOND.

small important things in inorganic

APPLICATION OF DIPOLE DIPOLE FORCE:

diple- dipole boiling point

Molecule with 0 dipole moment shows minimum boiling point and with maximum boiling point shows maximum boiling point.

ex: Cis isomers have high boiling point than trans.

MELTING POINT SYMMETRY PACKING 1/size

ex: s-block have low Melting point while d-block have high MP

Trans isomers have higher melting point than cis due 2 symmetry

Para isomers have high MP due 2 symmetry.

WHY ICE FLOATS ON WATER?

Ice has tetrahedral arrangement of water in which one H2O moleule is surrounded by 4 other H2O molecules and leave large vacant spaces due to which its volume increases and density decreases.

WHAT ARE ELATHRATES OF CAGE COMPOUNDS?

when noble gases like Ar, Kr, Xe are passed into H2O and suddenly freezed then dese gases get trapped in the vacant spaces of ice. such compounds are called cage-compounds.

ION DIPOLE FORCE:

When ionic compound or polar covalent compound is dissolved in water or polar solvents then

1. cation is surrounded by negative part of the solvent by ion dipole force for Group 1 and Group 2 cations. Coordination No is 6 but 4 Li and Be it is 4.

due to absence of d-orbital

NaCl when hydrated gives [Na(H2O)6]

Anion is surrounded by positive part of the solvent by ion dipole force

Which is:

a)H(delta +ve) if solvent is polar protic (which can donate H) and here the ion dipole force is called as H bonding

b) other dn H if the solvent is polar protic solvent and the ion dipole force is not the H bond

CONCLUSION: solvation energy is more in case of polar protic solvents hence the stability for the formation of cation or anion is more.

Q. Why does Li doesn't form alum?

A. for the formation of alum the required coordination number for the cation is six but Li has coordination number 4.

TO CHECK SOLUBILITY:

1.HYDRATION ENERGY

2. ABILITY TO GET POLARIZED

3.PHYSICAL STATE

find the solubility order of iodine, bromine and Chlorine:

answer: Cl2I2

EXPLANATION: I2 is polarized to a greater extent but due to its large size and its solid state it is less soluble.

Br2 secondly polarizes to a greater extent ( less dn I) and due to itz liquid nature it is more soluble in water.

INSTANTANEOUS DIPOLE INDUCED DIPOLE FORCES:

In non polar gaseous molecules due to collison or friction momentarily dipole is produced which in turn produced the dipole produce the dipole in the neighbouring moleule.

Ex: all noble gases

this force only is called as VANDER WAAL FORCE.

order of Vander waal force:

He

more the vander waal force more easy is the liquification.

Boiling Point: NH3 > PH3

H2O > H2S

HF > HCl <>

such order is due to H-bonding

and the boiling point increases downward due to increase in vanderwaal force of attraction.

Vander Waal force exists in all states of matter.

Liquids/solids in which molecules are held together by weak V.W. forces are volatile/sublime

VOLATILE LIQUIDS ACT AS GOOD FUELS.

INORGANIC 5 HYBRIDIZATION and GEOMETRY SIMPLIFIED

PS:THIS FORMULA WILL ALWAYS GIVE YOU THE CORRECT ANSWER

Just get through wid all this u'll find inorganic petty easy....

SHORTEST FORMULAE FOR HYBRIDIZATION:

No of valence electrons + No. of atoms attached to central atom

2

CONDITIONS:

1. Don't count the multiple bonded attached atoms.

2. Don't coun't odd or unpaired electrons.

after putting the values in the formula if ya get:

2 then compound is sp hybridized

3 then compound is sp2 hybridized

4 then compound is sp3/dsp2 hybridized

5 then compound is sp3d/dsp3 hybridized

6 then compound is sp3d2/d2sp3 hybridized

TO DIFFERENTIATE b/w sp3 and dsp2 hybridization and so on.

1. Easiest way is to check whether d-orbital present or not.

2. If the compound undergoes reaction with strong ligand than dsp2, dsp3,d2sp3 hybridization occurs.

3.If the compound undergoes reaction with weak ligand than sp3, sp3d, sp3d2 hybridization occurs.

TO IDENTIFY STRONG LIGAND AND WEAK LIGAND:

ALL NITROGEN CONTAINING except nitrate ion are strong ligands.

CO is exceptionally strong ligand...

ALL STRONG LIGANDS CAUSE PAIRING OF UNPAIRED ELECTRON IN D-ORBITAL.

GEOMETRIES:

REQUIRED (R): the total no. of atoms which are necessary for perfect geometry of that hybridization or number of hybrid orbitals.

AVAILABLE(A): Atoms attached.

R-A=no. lone pair

1.sp hybridization:

R=2, A=2

R-A=0

linear geometry, 0 dipole moment.

R=2, A=1

R-A=1 lone pair

so dipole moment is not 0.

2.sp2 hybridization:

a. R=3

-A=3

0 = no. of lone pairs.

Geometry: trigonal planar and dipole moment =0

b. R=3

A=2

lone pair = 1

Geometry: V shape/angular

c. R=3

A=1

lone pair = 2

Geometry: Linear

3. sp3

a. R=4

A=4

lone pair=0

Geometry: Tetrahedral

b. R=4

A=3

lone pair = 1

Geometry: pyramidal

c. R=4

A=2

lone pair = 2

Geometry: V-shape

d. R=4

A=1

lone pair = 3

Geometry: Linear

4.sp3d

a. R=5

A=5

lone pair = 0

Geometry: Trigonal Bipyramidal

b. R=5

A=4

lone pair = 1

Geometry: see-saw

c. R=5

A=3

lone pair = 2

Geometry: T-shape

d. R=5

A=2

lone pair = 3

Geometry: Linear

LONE PAIR CAUSE MAXIMUM repulsion so they will be placed at equitorial postion (larger bond angle)

5. sp3d2:

a. R=6

A=6

lone pair = 0

Geometry: square bipyramidal

b. R=6

A=5

lone pair = 1

Geometry:square pyramidal

c. R=6

A=4

lone pair = 2

Geometry : square planar.

PRACTICE PROBLEMS:

1. BeCl2 = 2+2 = 2 =sp Linear

2

2. CO2 = 4/2 =2 =sp Linear

3.XeOF2 = 8/2 + 2/2 = sp3d T-shape

4. XeF6 = 8/2 + 6/2 = Sp3d3 Distorted octahedral or caped octahedrl

SN2 mechanism

Overview:

The general form of the S_N2 mechanism is as follows:



nuc: = nucleophile
X = leaving group (usually halide or tosylate)

The S_N2 reaction involves displacement of a leaving group (usually a halide or a tosylate), by a nucleophile. This reaction works the best with methyl and primary halides because bulky alkyl groups block the backside attack of the nucleophile, but the reaction does work with secondary halides (although it is usually accompanied by elimination), and will not react at all with tertiary halides. In the following example, the hydroxide ion is acting as the nucleophile and bromine is the leaving group:

Because of the backside attack of the nucleophile, inversion of configuration occurs.

Solvents: Protic solvents such as water and alcohols stabilize the nucleophile so much that it won't react. Therefore, a good polar aprotic solvent is required such as ethers and ketones and halogenated hydrocarbons.

Nucleophiles: A good nucleophile is required since it is involved in the rate-determining step.

Leaving groups: A good leaving group is required, such as a halide or a tosylate, since it is involved in the rate-determining step

Reactions of Phenols

Compounds in which a hydroxyl group is bonded to an aromatic ring are called phenols. The chemical behavior of phenols is different in some respects from that of the alcohols, so it is sensible to treat them as a similar but characteristically distinct group. A corresponding difference in reactivity was observed in comparing aryl halides, such as bromobenzene, with alkyl halides, such as butyl bromide and tert-butyl chloride. Thus, nucleophilic substitution and elimination reactions were common for alkyl halides, but rare with aryl halides. This distinction carries over when comparing alcohols and phenols, so for all practical purposes substitution and/or elimination of the phenolic hydroxyl group does not occur.

1. Acidity of Phenols

On the other hand, substitution of the hydroxyl hydrogen atom is even more facile with phenols, which are roughly a million times more acidic than equivalent alcohols. This phenolic acidity is further enhanced by electron-withdrawing substituents ortho and para to the hydroxyl group, as displayed in the following diagram. The alcohol cyclohexanol is shown for reference at the top left. It is noteworthy that the influence of a nitro substituent is over ten times stronger in the para-location than it is meta, despite the fact that the latter position is closer to the hydroxyl group. Furthermore additional nitro groups have an additive influence if they are positioned in ortho or para locations. The trinitro compound shown at the lower right is a very strong acid called picric acid.

Why is phenol a much stronger acid than cyclohexanol? To answer this question we must evaluate the manner in which an oxygen substituent interacts with the benzene ring. As noted in our earlier treatment of electrophilic aromatic substitution reactions, an oxygen substituent enhances the reactivity of the ring and favors electrophile attack at ortho and para sites. It was proposed that resonance delocalization of an oxygen non-bonded electron pair into the pi-electron system of the aromatic ring was responsible for this substituent effect. Formulas illustrating this electron delocalization will be displayed when the "Resonance Structures" button beneath the previous diagram is clicked. A similar set of resonance structures for the phenolate anion conjugate base appears below the phenol structures.
The resonance stabilization in these two cases is very different. An important principle of resonance is that charge separation diminishes the importance of canonical contributors to the resonance hybrid and reduces the overall stabilization. The contributing structures to the phenol hybrid all suffer charge separation, resulting in very modest stabilization of this compound. On the other hand, the phenolate anion is already charged, and the canonical contributors act to disperse the charge, resulting in a substantial stabilization of this species. The conjugate bases of simple alcohols are not stabilized by charge delocalization, so the acidity of these compounds is similar to that of water. An energy diagram showing the effect of resonance on cyclohexanol and phenol acidities is shown on the right. Since the resonance stabilization of the phenolate conjugate base is much greater than the stabilization of phenol itself, the acidity of phenol relative to cyclohexanol is increased. Supporting evidence that the phenolate negative charge is delocalized on the ortho and para carbons of the benzene ring comes from the influence of electron-withdrawing substituents at those sites. The additional resonance stabilization provided by ortho and para nitro substituents will be displayed by clicking the "Resonance Structures" button a second time. You may cycle through these illustrations by repeated clicking of the button.

2. Substitution of the Hydroxyl Hydrogen

As with the alcohols, the phenolic hydroxyl hydrogen is rather easily replaced by other substituents. For example, phenol reacts easily with acetic anhydride to give phenyl acetate. Likewise, the phenolate anion is an effective nucleophile in S_N2 reactions, as in the second example below.

C₆H₅?OH + (CH₃CO)₂O C₆H₅?O?COCH₃ + CH₃CO₂H

C₆H₅?O^(?) Na⁽⁺⁾ + CH₃CH₂CH₃?Br C₆H₅?O?CH₂CH₂CH₃ + NaBr

3. Electrophilic Substitution of the Phenol Aromatic Ring

The facility with which the aromatic ring of phenols and phenol ethers undergoes electrophilic substitution has been noted. Two examples are shown in the following diagram. The first shows the Friedel-Crafts synthesis of the food preservative BHT from para-cresol. The second reaction is interesting in that it further demonstrates the delocalization of charge that occurs in the phenolate anion. Carbon dioxide is a weak electrophile and normally does not react with aromatic compounds; however, the negative charge concentration on the phenolate ring enables the carboxylation reaction shown in the second step. The sodium salt of salicylic acid is the major ptoduct, and the preference for ortho substitution may reflect the influence of the sodium cation. This is called the Kolbe-Schmidt reaction, and it has served in the preparation of aspirin, as the last step illustrates.

4. Oxidation of Phenols

Phenols are rather easily oxidized despite the absence of a hydrogen atom on the hydroxyl bearing carbon. Among the colored products from the oxidation of phenol by chromic acid is the dicarbonyl compound para-benzoquinone (also known as 1,4-benzoquinone or simply quinone); an ortho isomer is also known. These compounds are easily reduced to their dihydroxybenzene analogs, and it is from these compounds that quinones are best prepared. Note that meta-quinones having similar structures do not exist. The redox equilibria between the dihydroxybenzenes hydroquinone and catechol and their quinone oxidation states are so facile that milder oxidants than chromate (Jones reagent) are generally preferred. One such oxidant is Fremy's salt, shown on the right. Reducing agents other than stannous chloride (e.g. NaBH₄) may be used for the reverse reaction.
The position of the quinone-hydroquinone redox equilibrium is proportional to the square of the hydrogen ion concentration, as shown by the following half-reactions (electrons are colored blue). The electrode potential for this interconversion may therefore be used to measure the pH of solutions.

Quinone + 2H(+)	2e(?) ?2e(?)	Hydroquinone

Although chromic acid oxidation of phenols having an unsubstituted para-position gives some p-quinone product, the reaction is complex and is not synthetically useful. It has been found that salcomine, a cobalt complex, binds oxygen reversibly in solution, and catalyzes the oxidation of various substituted phenols to the corresponding p-quinones. The structure of salcomine and an example of this reaction are shown in the following equation. The solvent of choice for these oxidations is usually methanol or dimethylformamide (DMF).

Isomers

Isomers

Isomers are molecules with the same molecular formula, but different arrangements of atoms. There are different types of isomers, shown by the diagram on the right.

Functional Isomerism

Functional isomerism, an example of structural isomerism, occurs substances have the same molecular formula but different functional groups. This means that functional isomers belong to different homologous series.

ethanol	methoxymethane	C2H6O
		Alcohols have the hydroxyl group, ?OH. Ethers have the functional group R?O?R'.
propanal	propanone (acetone)	C3H6O
		Aldehydes and ketones both have the carbonyl group C=O. In ketones this is attached to two carbon atoms; in aldehydes it is attached to 1 or 2 hydrogen atoms.

Positional Isomerism

Positional isomerism, an example of structural isomerism, occurs when functional groups are in different positions on the same carbon chain.

butan-1-ol	butan-2-ol
but-1-ene	but-2-ene	Note: this is cis-but-2-ene, which has a geometric isomer called trans-but-2-ene (select here to find out more)
2-methylphenol	3-methylphenol	4-methylphenol

Chain Isomerism

Chain isomerism occurs when the way carbon atoms are linked together is different from compound to compound. It is an example of structural isomerism, and is also called nuclear isomerism.

pentane

2-methylbutane

2,2-dimethylpropane