Non-metals - hydrogen, Chemistry

Assignment Help:

 

HYDROGEN

Hydrogen is the natural element in the Universe and is a major constituent of stars. It is relatively much less common on Earth but nevertheless forms nearly 1% by mass of the oceans and crust, principally as water and in hydroxide and hydrates minerals of the crust.

The dihydrogen molecule H2 is the stable form of the element under simple conditions, although atomic hydrogen may be made in the gas phase at high temperatures, and hydrogen may convert a metallic liquid or solid at extremely high pressures. At 1 bar pressure, dihydrogen condenses to a liquid at 20 K and solidifies at 14 K, these being the minimum boiling and melting points for any substance except helium. The H-H bond has a dissociation enthalpy of 436 kJ mol-1 and a length of 74 pm. That is the shortest bond known, and one of the strongest single covalent bonds.

Although it is thermodynamically capable of reacting with many compounds and elements, these reactions usually have a large kinetic barrier and needs elevated temperatures and/or the use of catalysts.

 

Hydrides of metals

 

Not every metallic elements form hydrides. Those that do will be classified as follows.

 

  • Highly electropositive metals have solid hydrides regarded as containing the H- ion. They have structures same to halides, although the ionic character of hydrides is undoubtedly much lower. As like LiH (rocksalt structure) and MgH2 (rutile structure ;).

 

  • Some f- and d- block elements form hydrides that are often metallic in nature, and of variable (nonstoichiometric) composition. As like TiH2 and CeH2+x.

 

  • Some heavier p-block metals form molecular hydrides similar to those of nonmetals in the same group, stannane (SnH4) being and digallane (Ga2H6), both of very low stability.

 

 


Related Discussions:- Non-metals - hydrogen

Purification tecnics, how many methods to remove color impurities in chemic...

how many methods to remove color impurities in chemical compounds?

Sources of errore in thermogravimetry, plz can you send me or give me data ...

plz can you send me or give me data about my assignment topic which is mentioned above in title.it consist of 5 pages and only 5 sources are discussed in detail

The electron deficient compound, Which one is the electron deficient compou...

Which one is the electron deficient compound: (1) ICl                                                   (2)  NH 3                      (3)  BCl 3

Benzene is a very symmetrical compound, Benzene is a very symmetrical compo...

Benzene is a very symmetrical compound Benzene is a very symmetrical compound. The carbon framework is essentially a planar hexagon. Because of its resonance structures, all car

Crystal field splitting in octahedral complexes, Q. Crystal Field Splitting...

Q. Crystal Field Splitting in Octahedral Complexes? Let us consider an octahedral complex, ML6, where M is a metal ion and L stands for a ligand. The total charge on the comple

Analytical application, how we determine the qualitativ and quantitativ ana...

how we determine the qualitativ and quantitativ analysis of uv

Which group of elements is called alkaline earth metals, 1st A group becaus...

1st A group because the oxides and hydrides are alkaline in nature.

Equivalent mass, x gram of metal reacts with chlorine to form y gram of met...

x gram of metal reacts with chlorine to form y gram of metal chloride.calculate equivalent mass of metal.

Aufbau principle, Which of the following sequence is correct as per Aufbau ...

Which of the following sequence is correct as per Aufbau principle: (1) 3s (2)  1s (3) 2s (4) 2s Ans: 1s

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd