Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals.
The overlap of atomic orbitals means their partial merger, because of which their certain portion becomes common to both of them. The important conditions required for the linear combination of atomic orbitals to form molecular orbital are as follows:
a) The atomic orbital with one electron (completely half filled) can take part in combination or overlapping.
b) During the time of overlap, the combining orbitals must have opposite spins of electrons.
c) The combining atomic orbitals must have the same or nearly the same energy. This means that in a homo-nuclear molecule, the 1s-atomic orbital of an atom can combine with the 1s-atomic orbital of another atom and not with the 2s-orbital.
d) The overlapping must be maximum as far as possible.
What is meant by the term bond order? Calculate the bond order of: N2, O2,O2+,and O2-.
Use molecular orbital theory to explain why the Be2 molecule does not exist.
Explain the formation of H2 molecule on the basis of valence bond theory.
Compare the relative stability of the following species and indicate their magnetic properties:
O2,O2+,O2- (superoxide), O22-(peroxide)
Describe the hybridisation in case of PCl5. Why are the axial bonds longer as compared to equatorial bonds?
Which out of NH3 and NF3 has higher dipole moment and why?
Discuss the shape of the following molecules using the VSEPR model:
BeCl2, BCl3, SiCl4, AsF5, H2S, PH3
Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.
Write Lewis symbols for the following atoms and ions:
S and S2–; Al and Al3+; H and H–
Describe the change in hybridisation (if any) of the Al atom in the following reaction.
How do you account for the formation of ethane during chlorination of methane?
What are hybridisation states of each carbon atom in the following compounds ?
(i) CH2=C=O,
(ii) CH3CH=CH2,
(iii) (CH3)2CO,
(iv) CH2=CHCN,
(v) C6H6
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
What are the common physical and chemical features of alkali metals?
Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4
Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
What is the basic theme of organisation in the periodic table?
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Which one of the following will have largest number of atoms?
(i) 1 g Au (s)
(ii) 1 g Na (s)
(iii) 1 g Li (s)
(iv) 1 g of Cl2(g)
Predict the formula of the stable binary compounds that would be formed by the combination of the following pairs of elements. (a) Lithium and oxygen
(b) Magnesium and nitrogen
(c) Aluminium and iodine
(d) Silicon and oxygen
(e) Phosphorus and fluorine
(f) Element 71 and fluorine
Will CCl4 give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.
What do you understand by the terms:
(i) hydrogen economy
(ii) hydrogenation
(iii) 'syngas'
(iv) water-gas shift reaction
(v) fuel-cell ?
What are the major causes of water pollution? Explain.
Explain why cations are smaller and anions larger in radii than their parent atoms?
How many electrons in an atom may have the following quantum numbers?
(a) n = 4,
(b) n = 3, l = 0
If ten volumes of dihydrogen gas react with five volumes of dioxygen gas, how many volumes of water vapour would be produced?
What is the difference between the terms 'hydrolysis' and 'hydration'?
What are the major differences between metals and non-metals?
Thank you..it's helpful to me
Helpful! thank you
what about the symmetry
good for exam...