Unit 2: Bonding Flashcards
What charge do electrons have?
-1
What charge will an ion of lithium take?
1+ (one electron in the outer shell, needs to lose it)
What charge will an ion of beryllium take?
2+ (two electrons in the outer shell, needs to lose them both)
What charge will an ion of barium take?
2+ (group 2 so two electrons in the outer shell, needs to lose them both)
What charge will an ion of fluorine take?
1- (7 electrons in the outer shell, needs to gain one)
If something has gained electrons, what charge will it have?
Negative
If something has lost electrons, what charge will it have?
Positive (because they have lost a negative!)
What is reduction in terms of electrons?
Reduction is gain of electrons
What is oxidation in terms of electrons?
Oxidation is lossof electrons
Why do atoms transfer electrons in ionic bonding?
So that they can have full outer shells
Why do sodium ions and chlorine ions form an ionic bond?
There is an electrostatic force of attraction between oppositely charged ions
What is the name for a substance made of billions of oppositely charged ions joined together?
Giant ionic lattice
Define giant ionic lattice
A huge 3D network of ions
State the melting points of ionic substances
High
What is an ionic bond?
Strong electrostatic attraction between oppositely charged ions
Explain why ionic substances have high melting points.
Strong bonds between oppositely charged ions are hard to break
Will NaCl(s) conduct electricity?
No- (s) is solid
Will NaCl (aq) conduct electricity?
Yes (aq stands for aqueous which means it is dissolved in water)
Will NaCl (l) conduct electricity?
Yes- (l) is liquid or molten
Explain why ionic compounds do not conduct electricity when solid
Because the ions are not free to move
Explain why ionic compounds conduct electricity in solution
Because the ions are free to move
When do ionic bonds form?
Between a metal and a non-metal
Explain why ionic compounds conduct electricity when molten
Because the ions are free to move
What does soluble mean?
Dissolves in water
What does insoluble mean?
Does not dissolve in water
Explain why chlorine and fluorine form covalent bonds
They are both non-metals
Complete the sentence: In covalent bonds, electrons are _______________________
Shared
In ionic bonds, electrons are ___________________
Transferred
What is the name given to the structure of diamond, graphite and silicon dioxide?
Giant covalent
How many bonds does each carbon have in diamond?
4
Explain why diamond has a high melting point
Giant structure, Strong covalent bonds between the atoms, requires a lot of energy to break
Explain why most giant covalent substances do not conduct electricity (3 marks)
There are no electrons/ions/charged particles that are free to move
Explain why graphite conducts electricity
Has delocalised electrons between the layers that can move through the graphite
Explain why graphite can act as a lubricant
Weak forces between layers which are free to slide over each other
What is graphene?
One layer of graphite
What type of substance are methane and water?
Simple molecular (or simple molecules)
What is a molecule?
A group of atoms chemically bonded together
Describe the structure of simple covalent molecules
Strong covalent bonds between atoms, weak forces holding the molecules together
What are intermolecular forces?
Weak forces between molecules which hold them together
Explain why methane has a low melting point
It is a simple molecular substance with weak forces between the molecules (which are easy to break)
What is a polymer?
Millions of small molecules joined together in a chain to form a large molecule
Describe the main features of metals in terms of their structure
Positive metal ions arranged in layers with delocalised electrons
Explain why metals can conduct electricity
Delocalised electrons are free to carry charge
Explain why pure metals are soft
Layers of metal ions are free to slide over each other
What is an alloy?
A mixture of two or more elements, at least one of which is a metal
Give a reason for alloying a metal
To make it harder, to make it less reactive
Explain why alloys can be harder than pure metals
Different size of atoms disturb the layers to stop them sliding over each other
What is the reactivity series?
A list of elements ordered by their reactivity
What type of ion do metals from?
Positive Ion
What type of ion do non-metals form?
Negative ion
