Unit 5, 6 & 7 - Ionic Bonding/ Covalent Bonding/ Types Of Substance Flashcards
What are bonds?
Forces of attraction that hold atoms together.
What does more stable mean?
Less reactive
What is a noble gas atom?
An atom with a full outer shell.
What are ions?
Electrically charged particles formed when atoms lose or gain electrons.
What is a cation?
An ion that is formed from metals losing electrons and has a positive charge. (Losing electron)
What is an anion?
An ion that is formed from non-metals and has a negative charge. (Gaining electron)
What does the name change to when non-,metals form negative ions?
-ide
What are electrostatic forces?
The forces of attraction between all positively and negatively charged objects.
What is an ionic bond?
A bond between oppositely charged ions formed by the attraction between them.
What is an ionic bond formed from?
Metals and non-metals?
How is the group related to the number of electrons in the outer shell?
The group number is the same as the number of electrons in the outer shell.
What is a lattice structure?
The structure formed when billions of ions are closely packed together in a regular pattern.
What do ionic compounds form and why?
Crystals when solid because of their regular lattice structure.
Give 3 properties of crystals.
Particular regular shape
Flat surface
Sharp edges
Do ionic compounds have electrical charge?
No
What is a polyatomic ion?
A group of two or more atoms that have become charged.
What do all ionic compound contain?
Charged particles called ions
What are the ionic bonds?
The electrostatic force that holds the opposite charged ions
What do ionic compounds not contain?
Atoms or molecules
Are the electrostatic forces strong or weak?
Strong
What causes the substance to melt?
A lot of energy which separates the ions
If the forces holding ionic compounds is strong then…
They have high melting and boiling points.
Why would more energy be needed to separate ions?
If the charge is more than one
Do ionic compounds conduct electricity when solid?
No
Why do ionic compounds conduct electricity when they are molten or dissolved in water?
Because the charged particles are free to move
What is an aqueous solution?
When ionic compounds are dissolved in water to form the solution.
What are the anions attracted to?
The positive electrode called anode
What are the cations attracted to?
The negative electrodes called cathode
What enables ionic compounds to conduct electricity?
The ions being able to move, not the electrons
What bonds are in molecular substances?
String covalent bonds
What does the molecular formula show?
The number of atoms of each element bonded together in a simple molecule
What are covalent bonds formed between?
Non-metals
What happens in a covalent bond?
The atoms share electrons to make their outer shells full
What is a double covalent bond?
When more than one electron is shared
What is the valency of an element?
The number of covalent bonds formed to make full outer shells
What influences the properties of a compound?
The atoms and the type of bonding
What are the forces between the molecules called?
Intermolecular forces that are weak
Why does water have low boiling and melting points?
Because it doesn’t take much energy to over come the force.
What is an electric current
A flow of charged particles
Why can the electrons not flow in simple molecules?
The force between the electrons and the protons holds them in place
What are monomers?
Small, simple molecules
What is a polymer?
Monomers that are joined together in a chain.
Why do longer polymers have higher melting and boiling points?
They have more intermolecular forces and the long chain tends to get tangled up.
What are compounds and elements both examples of?
Molecules
What is an allotrope?
Different forms of the same element
How is fullerene formed?
Each carbon atom is covalently bonded to three other carbon atoms
What shape is fullerene?
Either spherical or tubular
Why is fullerene soft and slippery?
Because the intermolecular forces are weak
What is the formation of graphene?
A sheet of carbon atoms which are bonded to three other carbon atoms and can be rolled up.
Why is graphene the lightest material?
It is only one atom thick
Why is graphene a good electrical conductor?
It allows free electrons to move across the surface.
Give two example of giant structures of carbon
Diamond and graphite
What is different about giant structures?
They have huge three-dimensional networks of carbon.
Why does graphite and diamond have high melting and boiling points?
Many strong covalent bonds need to be broken
Why is there delocalised electrons in graphite
Because it has a layered structure so not all electrons are held in covalent bonds
Is graphite an electrical conductor?
Yes
Why is diamond no an electrical conductor?
All of the electrons are used in the covalent bonding
Why is graphite a good lubricant and soft
The forces between the layers are weak so the layers can slide.
Why is diamond an electrical insulator?
There are no free electrons to carry charge
Why is diamond very hard and rigid?
The structure arrangement is very rigid and the covalent bonds between each atom is very strong.
Give two general properties of metals
Any of: high melting points, shiny when polished, malleable, high density, good conductors of electricity
Give two properties of non metals
Any of: low melting points, not usually shiny, brittle, low density, poor conductors of electricity
How are atoms arranged in metallic bonding?
Same size, closely packed and in layers
In metallic bonding, why is there a ‘sea’ of electrons?
The outer shell electrons are lost from the atoms and are free to move anywhere throughout the metal
What is metallic bonding?
The electrostatic attraction between the positive ions and the negative delocalised electrons.
Is the attraction in metallic bonding strong or weak?
Strong
What does malleable mean?
They can be hammered into shape without shattering.
Why are metals malleable?
The layers of ions slide over each other and the sea of electrons holds the ions together so it doesn’t break
How do metals conduct electricity?
When a voltage is applied to either end of a metal, the electrons flow to one end causing an electrical current
What makes the electrical conductivity increase?
When the amount of delocalised electrons increase.
Are all electrons involved in the sea of electrons?
No, only from the outer shell
Give a weakness of dot cross diagram
It suggests that the electrons are different (dots and crosses)
Give a weakness of metallic model
Doesn’t show the ions will always be vibrating
Give weakness of 3D ball and stick model
It’s not sticks holding the atoms together
Give strength of dot cross diagram
Shows how electrons are shared
Give strength of metallic model
Shows how metal ions are held in a lattice structure
Give strength of 3D ball and stick model
Shows shape of structure
