43-45 - Covalent Bonding Flashcards
What is a covalent bond?
When electrons are shared by two or more atoms
What do hydrogen and chlorine have in common?
They only need one more electron
May form single covalent bonds
How many covalent bonds are there in methane?
4 (CH4)
If an element has 5 outer electrons, how many covalent bonds will it form?
3
What are some properties of simple molecular substances?
Weak intermolecular forces of attraction
Low MP and BP
Usually gases or liquids at room temperature
No ions = no electrical charge
What are some properties of macromolecules?
No charged ions
High MP and BP
Don’t conduct electricity (bar graphite)
What is an example of a simple molecular substance?
Chlorine
Oxygen
Water
What is a macromolecule?
Giant covalent structure
What are some examples of macromolecules?
Diamond
Silica
Graphite
What is the difference between diamond and graphite?
Different amount of covalent bonds per carbon
What are the properties of diamonds?
Four covalent bonds per carbon
Rigid structure
Strong and hard
Sparkly
What are the properties of graphite?
Each carbon forms 3 covalent bonds
Weak intermolecular forces between layers = slide over each other
Conducts heat and electricity
One delocalised electron per carbon atom
Why is diamond hard?
It is a macromolecule with lots of strong covalent bonds
Why is graphite soft?
Weak intermolecular forces between layers = sliding
Why does graphite conduct electricity?
Each carbon atom has a free electron to carry the current
