covalent compounds

Question 1

what is covalent bonding?
What do they contain?

Answer 1

A covalent bonding is a shared pair of electrons between atoms.
- non-metallic elements, e.g. oxygen,
- compounds of non - metals, e.g. sulfur dioxide

Question 2

Example of Covalent compound: a chlorine atom has seven electrons in its outer shell, what does it need to do to bond with another chlorine atom?

Answer 2

~ An electron from each atom is shared
~ This gives each chlorine atom eight electrons in the outer shell.
~ Each atoms now has a complete outer shell

Question 3

How can covalent bonds in molecules be shown?

Answer 3

Covalent bonds in molecules can be shown by drawing / using a dot and cross diagram.

Question 4

Properties and structure of covalent bonds:

Answer 4

. Covalent bonds are very strong.
. Some covalently bonded substances have simple structure e.g Water, hydrogen, Hydrogen chloride, Oxygen and nitrogen
. Others have giant covalent covalent structures, e.g. diamond and silicon dioxide.

Question 5

Simple Molecules

Answer 5

. Simple molecules contain a relatively small number of non-metal atoms joined together by covalent bonds.
. The molecules have no overall electrical charge, s they cannot conduct electricity.

Question 6

What are the substances that consist of simple molecules and why that is?

Answer 6

Usually Liquids and gases that have relatively low melting and boiling points.
This is because they have week intermolecular forces (forces of attraction between the molecules)

Question 7

How are the Intermolecular forces in simple molecules?

Answer 7

These intermolecular forces are very week compared to the strength of the covalent bonds in the molecules themselves. The larger the molecular = stronger the intermolecular forces between the molecular become.
Meaning that larger molecules have higher melting and boiling points.

Question 8

Giant covalent structures? Why is it that the bonds must be broken down, what does this mean?

Answer 8

All the atoms in giant covalent structures are linked by strong covalent bonds.
These bonds must be broken for the substance to melt or boil. This means that giant covalent structures are solids with very high melting and boiling points.

Question 9

Diamond, what is it? Its structure and bonding

Answer 9

Diamond is a form of carbon:
- I has a giant, rigid covalent
structure(lattice).
- Each carbon atom forms four strong covalent bonds with other carbon atoms.
- All the strong covalent bonds mean that it is a very hard substance with a very high melting point.
- There are no charged particles. so it does not conduct electricity.

Question 10

Graphite, what is it. Its structure and bonding.

Answer 10

Graphite is another form of carbon:
- It also have a giant covalent structure and a very high melting point.
- Each carbon atom forms three covalent bonds with other carbon atoms.
- This results in a layered hexagonal structure.
- The layers are held together by weak intermolecular forces.
- This means that the layers can slide past each other, making graphite soft and slippery.
- One electron from each carbon atom in graphite is delocalised.
- These delocalised electrons allow graphite to conduct heat and electricity.

Question 11

Silicon dioxide structure and atom

Answer 11

• Have a lattice structure similar to diamond:
• Each oxygen atom is joined to two silicon atoms.
• Each silicon atom is joined to tour oxygen atoms.