Structure, Bonding and properties Why do atoms bond together?

The Properties of simple covalent molecular substances -

Download 0.94 Mb.

View original pdf

Page	6/14
Date	05.10.2022
Size	0.94 Mb.
	#59665

1 2 3 4 5 6 7 8 9 ... 14

chemical bonding
0539 s18 qp 01

However , the electrical forces ** between molecules are weak and easily weakened further on heating
Most small molecules will dissolve in a solvent to form a solution .Large Covalent Molecules and their Properties

The Properties of simple covalent molecular substances -
small molecules!

The electrical forces of attraction, that is the chemical bond
*
, between atoms in any molecule are
strong and most molecules do not change chemically on moderate heating.(
* sometimes referred to as the
intramolecular bond
)

However
, the electrical forces
**
between molecules are weak and easily weakened further on
heating.

These weak attractions are known as
**
intermolecular forces and consequently the bulk material is not
usually very strong.

Consequently small covalent molecules tend to be volatile liquids, easily vapourised, or low melting
point solids.

On heating the inter-molecular forces are easily overcome with the increased kinetic energy gain of the particles and so have low melting and boiling points.

They are also poor conductors of electricity because there are no free electrons or ions in any state to carry electric charge.

Most small molecules will dissolve in a solvent to form a solution.
Large Covalent Molecules and their Properties

7
(macromolecules - giant covalent networks and polymers) It is possible for many atoms to linkup to form ab giant covalent
structure or lattice. The atoms are usually non-metals.

This produces ab very strong dimensional covalent bond network orb blatticeb.bThis gives them significantly different properties from the small
simple covalent molecules mentioned above.

This is
illustrated by carbon in the form of diamond
. Carbon can form four single bonds so each carbon bonds to four others etc.

This type of structure is thermally very stable and they have high melting

Download 0.94 Mb.

Share with your friends:

1 2 3 4 5 6 7 8 9 ... 14