Atomic structure, types of bondings Flashcards
The reason why the boiling point of nitrogen is very low even though the bond between the atoms in a nitrogen molecule is very strong is [2]
Weak intermolecular and low amount of energy required to break bonds between molecules; [1 mark]
covalent bonds don’t break [1 mark]
The difference in electrical conductivity between solid and liquid strontium chloride is
Ions cannot move in solid
OR
Ions can move in liquid; [1 mark]
The difference in electrical conductivity between liquid strontium chloride and liquid sulfur chloride is
No ions in sulfur chloride
OR
Sulfur chloride is covalent
OR
Sulfur chloride only contains molecules
OR
Only strontium chloride has ions; [1 mark]
Diamond is an example of
Giant covalent structure
Give an example of an ionic compound
Sodium chloride
Explain how simple covalent molecules have low melting and boiling points even though covalent bonds are strong [3]
1) Intermolecular forces that hold covalent molecules together
2) Intermolecular force is weak
3) Requires low energy to break
What is an ionic bonding?
Metal atom will transfer electrons to non metal so both can form a full outershell for stability
Why do diamond and graphite have high melting point [3]
1) It has billions of covalent bonds, it is 1 molecule for the entire structure.
2) Every carbon is bonded 4 times
3) No intermolecular forces
Why is graphite slippery
Weak forces of attraction between layers so it can slide over each other
What is the formation of positive ions called
Cation
Formation of negative ions
Anion
Define ionic bond
Strong electrostatic attraction between oppositely charged ions
5 properties of ionic compound
1) High melting & boiling point
2) good electrical conductivity when aqueous or
molten and poor when solid
3) Hard; [1 mark]
4) Soluble in water / insoluble in organic solvents; [1 mark]
5) Brittle
Draw the giant lattice of ionic compound
regular arrangement of
alternating positive and negative ions
Ionic bonds are formed between
Metals & non-metals
Explain why ionic structures have high melting points and boiling points [2]
Lots of strong electrostatic forces,
requires lots of energy to break
Explain why ionic structures have good electrical conductivity when aqueous or
molten but poor when solid [2]
1) Ions can flow around freely in an aqueous state which conducts electricity
2) Charges are immobile in solid state
Covalent bonding
When non-metals & non metals react and overlap pairs of electrons to get a full outershell
3 properties of covalent bonded compounds
1) Low melting & boiling point
2) Poor electrical conductivity
3) Covalent compounds are not soluble in water
Explain why covalent structures have poor electrical conductivity points [2]
1) There are no charged molecules flowing around
2) There are no free electrons
Negative ion
Anion
Positive ion
Cation
metallc bonding
the electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electron
3 properties of metallic bonding
1) good electrical conductivity
2) malleable and ductile
3) High melting and boiling points
Why are metallic bonding strong
Strong attraction between the positive metal ions and sea of delocalised electrons
Explain why metallic bonding have good electrical conductivity
delocalised electrons carry charge and move around structure freely
Explain why metallic bonding are malleable and ductile
Pure metals are arranged in layers and are the same size
2) Layers slide past each other when a force is extered
Describe diamond structure [3]
1) 1 carbon is bonded 4 more times
2) All covalent bonds are strong and identical
3) No intermolecular forces
Describe graphite structure
1) 1 carbon is bonded 3 more times that form layers of hexagons leaving 1 delocalised electron per carbon atom
2) Covalent bonds between layers are strong
3) Layers are attracted to each other by weak intermolecular forces
Why is graphite used as a lubricant
Layers can slide past each other
Why is graphite used as a electrode [3]
1) good conductor of electricity
2) chemically stable
3) Have high melting & boiling point
Why is diamond used as a cutting tool
Diamond have lots of strong covalent bonds making it a hard material that can cut through other materials
Describe the giant covalent structure of silicon(IV) oxide, SiO2 [2]
1) Each Silicon atom forms covalent bonds with 4 Oxygen atoms and each Oxygen atom in turn forms covalent bonds with 2 Silicon atoms
2) tetrahedral arrangement
Describe the similarity in properties between diamond and silicon(IV) oxide, related to their structures [4]
1) both have tetrahedral arrangement
2) SiO2 has lots of very strong covalent bonds and no intermolecular forces like diamond
3) both have high boiling & melting points
4) Both are hard
5) Silicion oxide can form acidic oxide
Define lattice
A repeating pattern of particles
Define electrostatic forces
he attractive or repulsive force between two electrically charged objects.
Ammonium
NH4
Hydroxide
OH
Nitrate
NO3
Sulfate
SO4
Carbonate
CO3
Hydrgoen carbonate
HCO3
