Bonding Flashcards
What are the two kind of substances that use covalent bonding?
Simple mollecular and Giant covalent
What are the boiling and melting points of simple mollecular like?
They are both very low
Why are the boiling melting points very low?
They have weak intermolecular forces holding them together so the molecules are easily parted from each other
What kind of state are most simple molecular substances?
Gas and liquid (at room temperature)
What are the boiling and melting points like in giant covalent?
Both are very high
Why are the boiling and melting points very high?
Because they have lots of strong covalent bonds which means it takes a lot of energy to break them all
Do they conduct electricity?
No (except for graphite)
Are they soluble or insoluble in water?
Insoluble
Give two examples of giant covalent substances
Diamond and graphite
In Diamond how many bonds does each carbon atom form?
4
In graphite how many bonds does each carbon atom form?
3
Between what kind of elements does covalent bonding occur?
Between non-metals
Give a definition for oxidation?
When an atom loses and electron
Give a definition for reduction?
When an atom gains an electron
What are cations?
Positive ions
What are anions?
Negative ions
What are the melting and boiling points like in giant ionic structures?
They are both very high
Why are the boiling and melting points like this?
There is a very strong electrostatic attraction between the two oppositely charged ions so a lot of energy is required to over come the attraction
Describe bonding in metals
Metals have a giant structure of positive ions surrounded by a sea of delocalised electrons. The attraction between the positive ions and electrons is called metallic bonding.
Explain why most metals are malleable
Because they have layers of ions that can slide of each other
Why are metals good conductors of electricity and heat?
The free electrons carry electrical current and heat energy through the material
When do ionic compounds conduct electricity and why?
When molten or in solution. They are made in a lattice so when solid don’t conduct electricity because the ions aren’t free to move around. When an ionic compound is dissolved or melted, the ions separate and are free to move in the solution. So they can carry electric current and so conduct electricity.
