Question

what are the exceptions in chemical bonding (for neet)​

Answer 1

Answer:

please mark as brainliest

Answer 2

Answer:

Chemical bond is generally formed by sharing or transfer of electrons .They are formed to become more stable and to complete octet state i.e.8 electrons in valence shell.

Some exceptions are

In compounds like BF3 (boron trifluoride) central atom is electron deficient (only 6 e- unlike octet)

In compounds such as PCI5 central atom has more e-than needed (10 in this case)

chemical bonding is basically electrical in nature, the result of attraction between bodies of opposite charge; bonding occurs when outer-shell electrons are simulatneously attracted to the positively-charged nuclei of two or more nearby atoms. Some exceptions

• Not all pairs of atoms can form stable bonds
• Different elements can form different numbers of bonds (this is expressed as "combining power" or "valence".)
• The geometric arrangement of the bonds ("bonding geometry") around a given kind of atom is a property of the element

There will be a lot, if you chose to be rigid with all the Concepts you read before.

1. Ionic compounds are water soluble. Now consider CaCO3, BaSO4, CsI, LiF -these are ionic but water insoluble/sparingly soluble.

2. BeO, MgO, Al2O3 have appreciable covalent character but these are high melting solids.

3. AgBr, AgBr are diamagnetic but colored. Due to greater polarisation.

4. Solid PCl5, solid PBr5, solid GaCl2, solid N2O5, solid N2O3 are ionic solids.

5. I4O9 is ionic solid , I(IO3)3

6. (XeF5)- has pentagonal planar geometry.

7. I2Cl6 has all atoms in same plane.

8. (CrO8)3– has four peroxy linkages (i.e, eight peroxy oxygens) and Cr (+5)

9. Two sulfur of H2S2O3 are in -2 & +6 oxidation state.

10. PH3, H2S and hydride of higher elements of group 15 and 16 have almost “no hybridisation”

11. Hybridisation in (CH5)+, triplet Carbene are sp2 hybridised.

12. CH2=C=CH2 is non-planar molecule, CH2=C=C=CH2 is planar

13. CH3-CH=S=O & H2N2O2 has Geometrical Isomerism.

14. Only four hydrogens of diborane can be methylated.

15. Solid BeCl2 is sp3 hybridised linear polymeric solid but BeCl2(g) is sp hybridised.

16. KHCO3 has dimeric hydrogen bonded (HCO3)- WHEREAS NaHCO3 has linear polymeric hydrogen Bonding hence KHCO3 is more soluble.

17. SnCl2 > SnCl4 melting point order

18. Bond angle: NF3 < NH3 but PF3 >PH3

19. Bond angle: Cl2O > H2O > F2O

20. C-F bond length: CH3F < CH2F2 < CHF3 < CF4

21. Bond angle: SO2 = SO3

22. O-O bond length: H2O2 > F2O2

23. Bond order of CO+ is 3.5

24. Ortho-cyanophenol has no chelation.

25. NCl3 + H2O gives NH3 and HOCl whereas PCl3 + H2O gives H3PO3 and HCl

26. Dipole moment: HF > H2O > NH3 but boiling point order: H2O > HF > NH3

27. HF has zig zag hydrogen Bonding where one HF molecule forms only two hydrogen Bonding.

28. Boiling point: H2O> H2Te > H2Se > H2S but BiH3 > SbH3 > NH3 > AsH3 > PH3

29. If H2O had no hydrogen Bonding: Its boiling point would have been 173 K

30. B2, C2 are examples of species having no sigma but only “pi” bonds.

31. Ionisation energy: N2 > O2 = Xe > NO

32. MALEIC ACID has Lesser pKa1 and greater pKa2 as compared to that of fumaric acid. Fir the same reason, ortho- nitrophenol is more acidic than para isomer.

33. Bond angle of NO2 is 115 degree and of (NO2)- is 136 degree

34. CF3 free radical is pyramidal, other organic free radical are Trigonal planar. ClO3 and ClO2 /NO2 free radical are of bent shape & pyramidal.

35. C3O2 and C2N4 are linear,

36. (CN2)2- cyanamide ion is isoelectronic and isostructural with CO2, N3–, N2O, (NO2)+

37. All C-C bonds in naphtalene are identical.(False) Etc..long.list..