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Thursday, August 6, 2020

Why the first ionization energy of group 15 elements much higher than those of corresponding group 14 elements?

The first ionization energy of group 15 elements much higher than those of corresponding group 14 elements this is due to increase in nuclear charge and extra stable configuration of the elements of this group. The extra stability of configuration is attributed to the exactly half filled p – orbitals in their valence shells.

Related Questions:

Which is more basic N(CH3)3 or N(SiH3)3 , explain?

Are all the five bonds of PCl5 equivalent? Justify your answer.

Trisilyl amine, N(SiH3)3 is planar whereas trimethyl amines N(CH3)3 is pyramidal. Explain why?.

What are common structural features of oxides (P4O6 and P4O5) of phosphorous?

What are the structural difference between oxides ( P4O6 and P4O10) of phosphorous?

What are abnormal behaviour of Nitrogen atom as compared to other family members?

What is product obtained when N2O5 is treated with NaCl?

What is metaphophoric (HPO3)?

Phosphorus can form PCl5 but nitrogen can not form NCl5 why?

Why PCl3 hydrolysed while NCl3 can not be hydrolysed? 

Why bond angle of hydrides of group 15, decreases down the group?

What is "calgon" ? Give structure and its uses?

Why nitrogen shows catenation properties less than phosphorus?

Why Nitrogen is fairly inert gas?

Why Nitrogen (N2) is less reactive at room temperature?

Why Nitrogen dioxide (NO2) dimerises to form Dinitrogen tetraoxide (N2O4)?

Why Nitrogen dioxide (NO2) is coloured but Dinitrogen tetraoxide (N2O4) is colourless?

Hypophosphorous acid (H3PO2) and Phosphorous acid (H3PO3) act as as good reducing agents while H3PO4 does not.Why?


Wednesday, July 22, 2020

Metallurgy- Extraction of elements, and purification methods:

METALLURGY-INTRODUCTION:
PYROMETALLURGY:

How to determine Basic order of different amines and it derivatives ?

  1. How is base strength related to the availabihty of the electron-pair?
  2. Amines are more basic than ammonia why?
  3. What is relative basic strength order 1° amines , 2°amines and 3° amines ? Explain:
  4. Give an explanation for the fact that Guanidine NH=C(CH3)2 is a stronger base than most of amines?
  5. Arrange in correct order of basic Character of aniline, pyrrol, pyridine and piperidine?
  6. What is correct basicity order of pyridine, pyridazine, pyrimidine and pyrazine ?
  7. Give an explanation for the fact that Guanidine NH=C(CH3)2 is a stronger base than most of amines?
  8. Arrange in correct order of basic Character of aniline, pyrrol, pyridine and piperidine?
  9. What is correct basicity order of pyridine, pyridazine, pyrimidine and pyrazine ?
  10. Why pyridine is more basic than Pyrrole?
  11. Why pyrimidine is less basic than pyridine?
  12. Imidazole is more basic than pyridine? Why?
  13. Biological Important of Imidazole and structure:
  14. Pyridine is almost 1 million times less basic than piperidine? Why?
  15. Cyclohexylamine amine is the stronger base than Aniline? Why?
  16. Tetrahydroquinoline amine is the stronger base than Tetrahydroisoquinoline? Why?
  17. Arrange the following in the order of increasing basicity : p-Toluidine, N, N-Dimethyl-p-toluidine, p-Nitroaniline, Aniline. (I.I.T.1986)
  18. Arrange the following in the increasing order of their acid strength : Methyl amine, Dimethyl amine, Aniline, N-methyl aniline (I.I.T, 1988).







Monday, July 20, 2020

What are Zeeman and Stark effects? Were they explained by the Bohr’s theory?

The splitting of spectral lines into many components in the presence of a magnetic field is called Zeeman effect.

Analogously, the splitting of spectral lines into many components in the presence of an electric field is called Stark effect. 
These effects could not be explained within the framework of Bohr's theory and required the presence of multiple non-circular orbits corresponding to each energy level. An effort, with some degree of success, was made by Sommerfeld to explain these phenomena by invoking multiple elliptical orbits corresponding to each energy level. The Bohr Sommerfeld theory was ultimately discarded along with Bohr's model for other reasons.

Ionization energy of Boron is smaller than Beryllium even though effective nuclear charge is higher?

The electronic configurations of Boron and Beryllium are (5B=1S2,2S2,2p1) and (4Be =1S2,2S2).

In Boron the outermost electron is present in the 2p orbital (low penetration power) and is less strongly bound than the electron present in a 2S orbital of Beryllium (Have more penetration power), which will has a higher Zeff. It is easier to ionize the Boron atom.


Related Questions:

(1) What are the Amphoteric metals ? gives Examples.

(2) Name of total metalloids present in periodic table ?

(3) Total numbers of elements which are liquid at normal temperature is ?

(4) What is Mendeleev's periodic table ? give important features and draw back of Mendeleev's table.

(5) What is atomic density ? give the periodicity of atomic density in periods and groups.

(6) What is atomic volume ? and what is periodicity of atomic volume in groups and periods ?

(7) Why there are 2, 8 and 8 elements in first, second and third periodic of periods table respectively ? Explain.

(8) In alkali metal group which is the strongest reducing agent in aqueous solution and why?

(9) The electron affinity of sulphur is greater than oxygen. Why?

(10) The first ionization energy of carbon atom is greater than that of boron atom, whereas reverse is true for the second ionization energy. Explain.

(11) The electronegativities of B, Al, Ga are 2.0, 1.5, 1.6 respectively. The trend is not regular. Explain.

(12) Li2CO3 decomposes on heating but other alkali metal carbonates don’t. Explain.

(13) Of all noble metals, gold has got a relatively high electron affinity. Explain.

(14) What are the increasing order of ioni radii of first group elements in water ?

(15) What are the increasing order of molar conductivity of first group elements in water ?