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

By which cycle form a helium nucleus?, Q) Inside the sun four hydrogen nucl...

Q) Inside the sun four hydrogen nuclei combine to form a helium nucleus by which cycle? Ans) Proton-proton cycle.

Illustrate matter, Matter is anything that has mass and takes up space. The...

Matter is anything that has mass and takes up space. The term matter refers to all the materials, or "stuff," making up the universe. Everything you see around you is matter. The c

Colligative properties, some examples of RELATIVE MOLECULAR MASS OF SOLUTES...

some examples of RELATIVE MOLECULAR MASS OF SOLUTES BY RELATIVE LOWERING OF VAPOR PRESSURE

The correct electronic configuration of ti(z= 22) atom is, The correct ele...

The correct electronic configuration of Ti(Z= 22)  atom is: (1) 1s 2 , 2s 2 , 2p 6 , 3p 6 , 4s 2 , 3d 2 ,   (2) 1s 2, 2s 2 , 2p 6 , 3p 6 , , 3d 4 ,         (3) 1s 2 , 2s

Properties of bi-phenyl - hydrocarbon, Properties of Bi-phenyl - Hydrocarbo...

Properties of Bi-phenyl - Hydrocarbon Bi-phenyl is a colourless solid, melting point 71°C. It goes through usual electrophilic replacement reactions. As aryl set are electron w

Show milk – quality specification, Q. Show Milk – quality specification? ...

Q. Show Milk – quality specification? Milk is a whole, clean, fresh lacteal secretion obtained by complete milking of one or more healthy milch animals. Milking is not done 1

Define and classify alkanes, Question 1 Write a short note on the followin...

Question 1 Write a short note on the following Photoelectric effect Transition Elements Hydrogen bonding Standard entropy Question 2 What are aromatic acids

Organic compounds , What Is The B...

What Is The Benefits Of Alkenes?

Classification of proteins - globular proteins, Globular proteins These...

Globular proteins These proteins comprise more or less spherical shape (compact structure). α-helics are firmly held up by weak attractive forces of numerous types that are Hyd

Coordination position isomerism, what is the geometry of coordination...

what is the geometry of coordination position isomers

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