2. Bonding, structure and the properties of matter (covalent bonding and the structure and bonding of carbon) Flashcards
What is covalent bonding?
The sharing of electrons between non-metals
Why do non-metals gain electrons?
Because it is energetically unfavourable for them to lose electrons, so they gain electrons
What do covalent bonds form?
Covalent compounds
What 2 types of molecules can be formed as a result of covalent bonding?
- Simple covalent molecules
- Giant covalent structures/lattices
What are simple covalent molecules?
Molecules containing few atoms which are covalently bonded. Like H2, 02
What are examples of simple molecular covalent structures?
(H2, O2, Cl2, CH4)
What are the properties of simple molecular covalent substances?
- low melting and boiling points
- they are gases at room temperature
- cannot conduct electricty
Why do simple molecular substances have low melting and boiling points?
- The intermolecular forces between the molecules are very weak
- So not a lot of energy is required to overcome them
Why do simple covalent molecules not conduct electricity?
Because there are no free electrons or ions to carry charge
What are examples of giant covalent structures/lattices?
- Diamond
- Graphite
- Silicon dioxide
What does allotrope mean?
Different forms of something
What are the 3 giant covalent structures allotropes of?
Carbon
How many bonds can carbon atoms make in diamond?
4 bonds
What is diamond made up of?
Carbon atoms covalently bonded 4 times
What are the properties of diamond?
- High melting and boiling points due to incredibly strong covalent bonds
- Found as a solid
- Very rigid structure
- Does not conduct electricity because there are no free electrons or ions to carry charge