The term stereogenic center or stereocenter:

A stereogenic center is defined as an atom on which an interchange of any two atoms or groups result in a new stereoisomer, When the new stereoisomers is an enantiomer ,the stereocenter is called chiral center. All stereocenters are not tetrahedral.

First and second are enantiomers (non superimposible mirror images), Hence the steriocentre is a chiral centre.

III and IV are not enantiomers. they are diasteriomers hence in this case sterio centres are not chiral centres. Also these are not tetrahedral. Thus, all chiral centres are sterio centres but all steriocentres are not chiral centres. If a molecule contains only one chiral centres it must be chiral. Molecule containing two or more 

chiral centres may or may not be chiral. For example: meso tartaric acid has two chiral centres but it is achiral.

Realated Questions:

(1) How many cyclic isomers possible of (C6H12) Hexene?

(2) How many cyclic isomers possible of (C5H10) pentene?

(3) Write the major and minor product of hydration of 1-Methylcyclopent-1-ene in acidic medium?

(4) Why enol form of Beta Dicarbonyl compound more stable than those of monocarbonyl compounds?

(5) Why enol form of phenol is more stable than its keto isomers?

(6) What is Imine-Enamine tautomerism?

(7) The term Asymmetric center and chiral center :

The term Asymmetric center and chiral center :

Three terms are used to designate, a carbon atom bonded tetrahedrally to four different substituents in a chiral molecule: 

Asymmetric atom, chiral center or stereocenter.

Let us understand chiral and achiral center taking few more examples.

Related Questions:

(1) Although anti conformation is more stable than the gauch conformation but in some cases gauch or skew conformation is more stable than the anti confirmation why?

(2) Arrange the following in the order of their increasing order of expected enol content. H3C-CO-CH2-CHO, H3C-CO-CH3, H3C-CHO and H3C-CO-CH2-CO-CH3 .

(3) Write total fuctional isomers of molecular formula C5H10.

(4) How to find number of stereoisomers in a large compound containing chiral centres ?.

(5) How to find number of stereoisomers in a large compound (polyenes) containing double bonds?

(6) How do you calculate the number of all possible structural isomers for alkanes?

(7) How many cyclic isomers possible of (C6H12) Hexene?

(8) How many cyclic isomers possible of (C5H10) pentene?

(9) Write the major and minor product of hydration of 1-Methylcyclopent-1-ene in acidic medium?

(10) Why enol form of Beta Dicarbonyl compound more stable than those of monocarbonyl compounds?

(11) Why enol form of phenol is more stable than its keto isomers?

Nature of Transition Metals Oxides:

The oxides of  transition metals will be acidic , basic or amphoteric  as camparative with its oxidation state. The follow following trends.

Trends (1): The higher oxidation state of the central metal atom , the more covalent character  and oxide will be more acidic in nature.

Trends (2): The Lower oxidation state of the central metal atom , the more ionic character and oxide will be more basic in nature.

Trends (3): The moderate oxidation of central metal atom oxide will be amphoteric in Nature .

Oxidation State	Nature of Oxides
+1 , +2 , +3	Basic ,Except Cr2O3
+4	Amphoteric e.g. MnO2
+5, +6, +7	Acidic,V2O5,CrO3,MoO3,Mn2O7,OsO4

Example of oxides of (Mn):

Oxides	Oxidation state	Nature
MnO	+2	Basic
MnO2	+4	Amphoteric
Mn2O7	+7	Acidic

Example of oxides of (Cr):

Oxides	Oxidation state	Nature
CrO	+2	Basic
Cr2O3	+3	Amphoteric
CrO3	+6	Acidic

Related Questions:

(1) What is the structure and structural characteristic of dichromate kon (Cr2O7)-2?

(2) What is the structure and structural characteristic of dichlorine heptaoxide (Cl2O7)-2?

Oxides:

(1) Normal Oxides:

(2) Sesqui Oxides:

(3) Mixed Oxides:

(4) Peroxides:

(5) Super Oxides:

(6) Suboxides:

(7) Perovskites:

(8) Spinel Oxides:

(9) Cage like Oxide:

Others oxides

(1) Crystal lattice Structure of Oxides:

(2) Corundum (Al2O3) type Structure:

(3) What are the normal spinel structures?

(4) What are the inverse spinel structures?

(5) Rutile (TiO2) type Structure:

(6) Pervoskite (ABO3) type structure:

Coordination Compounds or complex:

8.1 Double salt or lattice salts
8.2 Coordination or complex salts
8.3 Structure and terminology
8.4 Nomenclature of complex compounds
8.5 Type of ligands
8.5 Special ligands
8.6  Bonding  in complexes:
8.6.1(A) Werner's theory of coordination complexes:

8.6.1(B) Werner’s Theory and Isomerism:

8.6.1(C) Examples Based on Postulates of Werner’s Theory:

8.6.2 Sidwick theory and EAN rule

8.6.3 Valence bond theory
8.6.4 Spectrochemical series

8.6.5 Crystal field theory:

8.6.5 (A) Crystal field splitting in octahedral complexes:

8.6.5 (B) Crystal field splitting in tetrahedral complexes:

8.6.5 (C)Crystal field splitting in square planar complexes:
8.6.5 (D) Crystal field stabilisation energy (CFSE)

8.8.1 Synergic bonding:
8.9 .1 Organometallic compounds

8.10.1 Concept of colour in metal complexes :

Related Question:

(1) Although both [Mn(H2O)6]2+ and [FeF6]3- have a d5 configuration and high-spin complexes. But the dilute solutions of Mn2+ and Fe +3 complexes are therefore colorless. Why?

(2) Which of the Complex of the following pairs has the highest value of CFSE?

(3) Colour of Complexes due to charge transfer:

(4) Why violet colour of [Ti(H2O)6]Cl3 disapear (colourless) on heating heating ? 

(5) Why [Ni(CN)4]-2 is colourless while [Ni(H2O)4]-2 although both have +2 oxidation state and 3d*8 configuration ?

(6) Why [FeF6]3– is colourless whereas [CoF6]3– is coloured ?

(7) Why Fe(CO)5 is colourless while Fe(bipy)(CO)3 is intensely purple in colour ?

(8) Why all the tetrahedral Complexes are high spin Complexes ?

(9) Why transition metals and their compounds are act as catalyst?

(10) Why all the tetrahedral Complexes are high spin Complexes ?

Banana Bond or 3C-2e Bond or Bridge bond or structure of B2H6 and Al2(CH3)6:

(1) Formation of 3C-2e bond in B₂H₆ is best explain by MOT and total number of bond in B₂H₆ is 6 (3C-2e=2 and 3C-4e=4)

(2) Bridge bonds are longer than terminal bond because at bridge bonds electrons are delocalized at three centres

(3) Bond energy (441kj/mole) of B-H-B bond is greater than bond energy (381 K j/mole) of   B-H bond.

(4) Hybridization of B atom is sp3, so non planer, and non polar (U=0)

(5)  B₂H₆ Methylated up to B₂H₂ Me₄

(6) B₂H₆ is hypovalent molecule hence act as Lewis acid and undergoes two type of cleavage when react with Lewis base:

(A) UNSYMETRICAL CLEAVAGE: 

B₂H₆ Undergo unsymmetrical cleavage with small size strong Lewis base like NH₃ NH₂Me and NH (Me) ₂ etc.

(B) SYMETRICAL CLEAVAGE:

B₂H₆ undergoes symmetrical cleavage with large size weak Lewis base like PH₃, PF₃,Me₃N , OEt , OMe₃, pyridine , THF , Thiophene , SMe₂ ,Set₂

Related Questions: 

(1) Why aqueous solution of AlCl3 is acidic in nature ?

(2) What happen when aq AlCl3 react with Acid or Base?

(3) Although anhydrous aluminium chloride is covalent but its aqueous solution is ionic in nature. Why?

(4) Why BF3 do not exist as dimer?. Explain.

(5) Why B-F bond length in BF3 is shorter (130 pm) than B-F bond Iength in BF4- (143 pm)?. Explain.

(6) B-F bond length in BF3 is shorter than B-F bond length in (BF4)- why?

(7) When B2H6 is allowed to react with following Lewis bases, then how may given Lewis base form adduct through symmetrical Cleavage of B2H6.

(8) What is product of reaction between diborane (B2H6) and ammmonia (NH3)?

(9) Why methylation of Diborane (B2H6) replace four hydrogen only ?

(10) What is Use of Boric Acid?

(11) What is use of Orthoboric acids?

(12) What is basicity of "Boric acid" ?

(13) Why Boric acid exist in solid state ?

(14) What is structure of solid Ortho Boric acid ?

(15) What is effect of heat on Borax?

(16) What is the structure of trimetaboric acid and trimetaborate ion?

(17) What is the Sodium per borate ,give the structure and its uses?

(18) Why aqueous solution of borax reacts with two moles of acids ?

(19) What is the molecular formula of Borax ?

(20) Why Boric acid become strong acid in the presence of cis 1,2-diol or 1,3-diol ?

(21) Why Borazine is more reactive than benzene towards Electrophic Aromatic substitution reactions ?

(22) Why Borazine (B3N3H6) is also known as inorganic benzene ?.

(23) Four-center two-electron bond (4C-2e Bond): Structure of AlCl3:

(24) What is the difference between the structure of AlCl3 and diborane?