Topic 2: Bonding, Structure And Properties Of Matter Flashcards
What are the 4 types of chemical bonds?
Compounds
Ionic
Covalent
Metallic
Which 3 of the chemical bonds are the strong bonds?
Ionic
Covalent
Metallic
What is a compound?
2 or more elements chemically combined
Where does ionic bonding occur?
In compounds formed from metals combined with non-metals.
Ionic particles are __________ charged ____ .
Oppositely
Ions
Where does covalent bonding occur?
In most non-metallic elements and in compounds of non-metals.
Covalent particles are atoms which share _____ of _________ .
Pairs
Electrons
Where does metallic bonding occur?
In metallic elements and alloys.
Metallic particles are atoms which share ___________ electrons.
Delocalised
Electron transfers to form ionic compounds can be represented by…
Dot and cross diagrams
What direction do ionic compound forces act in and why?
All directions as it is a giant 3D structure.
How are ionic compounds held together?
By strong electrostatic forces of attraction between oppositely charged ions.
What is covalent bonding?
When atoms share one or more pairs of electrons
What are polymers?
Large covalently bonded molecules
What do giant covalent structures consist of?
Many atoms covalently bonded in a lattice structure.
What is another word for a giant covalent structure?
Macromolecules
Name 2 examples of giant covalent structures.
Diamond
Silicon Dioxide
What does the delocalised electron system consist of in terms of metallic bonding?
Electrons lost from the atoms to form positive ions.
What does the bonding in a metal consist of (metallic bonding)?
Positive ions (atoms that have lost electrons) and delocalised electrons attached in a regular pattern.
___________ electrons are free to move through the structure (in terms of metallic bonding)
Delocalised
Why are metallic bonds so strong?
Because the delocalised electrons are shared through the structure.
What are the three states of matter?
Solid
Liquid
Gas
What takes place at the melting point?
Melting and freezing
What takes place at the boiling point?
Boiling and condensing
The stronger the forces between the particles the higher the…
Melting point and boiling point of the substance.
What are the 4 state symbols in chemical equations?
(S) solid
(L) liquid
(G) gas
(Aq) aqueous solution
Why do ionic compounds have high melting and boiling points?
Because a lot of energy is required to break the strong bonds.
When can ionic compounds conduct electricity and why?
When they are melted or dissolved in water because the ions are free to move and carry a current.
Why can’t ionic compounds conduct electricity in a solid?
Because the ions are in fixed positions.
Smaller molecules have ____ intermolecular forces.
Weak
Intermolecular forces increase with the size of the _________ , so larger _________ have ______ melting and boiling points.
Molecule
Molecules
Higher
True or false: “small molecules have an overall electric charge”
False: small molecules DO NOT have an overall electric charge, so they cannot conduct electricity.
Polymers have very large _________ .
Molecules
How are polymer molecules linked to other atoms?
By strong covalent bonds.
Why are polymers solid at room temperature?
Because the intermolecular forces between polymer molecules are quite strong.
What are alloys made from?
2 or more different types of metals.
Why are alloys harder than pure metals?
Because the different sized atoms distort the layers in the structure, making it difficult for the layers to slide over each other.
Why are metals good conductors of electricity?
Because the delocalised electrons in the metal carry an electrical charge.
Why are metals good conductors of thermal energy?
Because energy is transferred by the delocalised electrons.
