Topic 1c- Bonding (Paper 1 + 2) Flashcards
What is the relative mass of an electron?
1/1840
What is the relative mass of a proton?
1
What is the relative mass of a neutron?
1
What is the relative charge of an electron?
-1
What is the relative charge of a neutron?
0
What is the relative charge of a proton?
+1
What are isotopes?
Isotopes are atoms of the same element that have a different number of neutrons and therefore also a different mass number.
What is relative atomic mass?
The relative atomic mass is the weighted average mass of an atom of an element compared to 1/12 the mass of a Carbon atom (12).
How many electrons are in each shell (up to 3rd)?
2,8,18 (but behaves like 8)
What holds together a substance that is ionically bonded?
Positive and negative ions are held together by electrostatic forces of attraction in a giant lattice structure.
What holds together a substance that is ionically bonded?
Positive and negative ions are held together by electrostatic forces of attraction in a giant lattice structure.
What are properties of ionic substances?
High melting and boiling points.
Hard but brittle.
Generally soluble in water.
Don’t conduct electricity in a solid state.
Do conduct electricity as liquids i.e. when molten or dissolved in water.
What are ions?
Ions are charged particles.
What substances form covalent bonds?
Two or more non-metals.
What substances form ionic bonds?
A metal and a non-metal.
What substances form metallic bonds?
Two or more metals.
What are simple covalent substances?
Composed of separate molecules bonded strongly together by covalent bonds. (e.g. H20, CH4, O2…)
What are giant covalent substances?
Giant covalent substances contain millions of atoms bonded together by many strong covalent bonds to form a giant molecule or macromolecule. (e.g. diamond and graphite.)
Why are the melting and boiling points of covalent substances low?
Only need to overcome weak intermolecular forces that need little energy.
Why are simple covalent substances poor conductors?
No ions or free electrons present.
Why do simple covalent substances have poor solubility in water?
No charged particles present to be attracted to water molecules.
What are the physical properties of simple covalent substances?
Low melting and boiling points.
Poor electrical conductivity.
Poor solubility in water.
What are the physical properties of metallically bonded compounds?
High melting and boiling points.
Malleable and ductile.
Good conductors of electricity.
Good conductors of heat.
Why do metallically bonded substances have high melting and boiling points?
Lots of energy is needed to overcome the forces of attraction between the positive ions and delocalised electrons.
Why are metallically bonded substances malleable and ductile?
Layers of ions can slide over each other when force is applied.
Why are metallically bonded substances malleable and ductile?
Layers of ions can slide over each jother when force is applied.
Why are metallically bonded substances good conductors of electricity?
The electrons in the sea of delocalised electrons are free to move and can flow when a potential difference is applied.
Why are metallically bonded substances good conductors of electricity?
The electrons in the sea of delocalised electrons are free to move and can flow when a potential difference is applied.
Why are metallically bonded substances good conductors of electricity?
The electrons in the sea of delocalised electrons are free to move and can flow when a potential difference is applied.
Why are metallically bonded substances good conductors of electricity?
The electrons in the sea of delocalised electrons are free to move and can flow when a potential difference is applied.
Why are metallically bonded substances good conductors of heat?
The delocalised electrons gain kinetic energy when heated and move faster through the material transferring heat.
What is an alloy?
Mixtures of metals where the metals are metallically bonded in a giant metal lattice.
Why are alloys not regarded as compounds?
- The metals can be separated by physical methods.
- There is no fixed ratio for an alloy, unlike atoms in a compound.
Why are alloys generally tougher and less malleable than pure metals?
The foreign metal atoms prevent the layers of metal atoms from sliding over each other, therefore they are stronger.
