Covalent Bonding Flashcards
What determines the length of a single covalent bond?
The size of the atom - the distance between the nucleus and outer shell electron.
The charge density - which affect size.
Which out of single bonds, double bonds and triple bonds contain the longest and shortest bond?
Longest bond > single bond C——C
Middle length > double bond C==C
Shortest bond > triple bond C≡O
Predict which bond is longer…
P-P or S-S
C≡N or C≡C
Cl-H or Br-H
C-C or C=C
N-O or P-O
Longest bonds…
P-P or S-S > P-P
C≡N or C≡C > C≡C
Cl-H or Br-H > Cl-H
C-C or C=C > C-C
N-O or P-O > N-O
What increases the length of a covalent bond?
The greater the SIZE of the atom, the longer the covalent bond.
The greater the CHARGE density of the atom, the longer the covalent bond.
Describe the relationship between bond length and bond strength.
As bond length decreases, the bond strength increases.
As bond length increases, the bond strength decreases.
Predict which bond is the strongest and weakest…
C-C
N-N
N=N
Strongest > N=N
Weakest > C-C
An N-N bond should be stronger than a C-C bond since it is shorter, and an N=N bond is stronger than an N-N bond since double bonds are shorter.
What is a covalent bond?
When intermolecular forces of attraction form between atoms that share 1 or more pairs of electrons in a simple molecular or giant covalent structure.
What is the force of attraction formed between molecules?
Intermolecular forces of attraction.
What should I always remember about covalent bonds?
Covalent bonds are STRONG, not weak.
Intermolecular forces are WEAK.
What is a single bond?
When atoms share 1 pair of electrons.
What is a double bond?
When atoms share 2 pairs of electrons,
What is a triple bond?
When atoms share 3 pairs of electrons.
List everything about covalent bonding you can remember.
Non-metal and non-metal.
STRONG covalent bonds.
WEAK intermolecular forces of attraction.
Electrons are SHARED.
Simple molecular structure
Giant covalent structure
Give examples of simple molecules.
Cl₂
N₂
H₂
CO₂
H₂O
CH₄
NH₄
H₂O₂
Give examples of giant covalent structures.
Diamond (each carbon bonds to 4 other carbons)
Silicon dioxide (SiO₂)
Graphite (each carbon bonds to 3 other carbons)
Graphene (1 layer of graphite)
Buckminster fullerene (C₆₀)
Carbon nanotubes
What are some properties of simple covalent structures?
Low MP/BP
Do NOT conduct electricity
Insoluble (usually)
What is a simple covalent molecule?
Molecules joined by covalent bonds with weak forces between them.
Explain why simple covalent molecules have a low melting and boiling point. [2 marks]
Intermolecular forces of attraction are WEAK - requires less energy to overcome the forces.
Explain why simple covalent molecules cannot conduct electricity.
Contains no charged particles (ions/delocalised electrons) that can move - molecules are neutral.
What is a giant covalent structure?
Lattice structure where atoms are joined by covalent bonds.
What are some properties of giant covalent molecules?
High MP/BP
DO NOT conduct electricity (except graphite)
Insoluble
Explain why giant covalent molecules have a high melting and boiling point. [2 marks]
Contain MANY strong covalent bonds - requires more energy to overcome.
Explain why giant covalent molecules cannot conduct electricity, and why graphite CAN conduct electricity.
Contains no charged particles (ions/delocalised electrons) that can move - molecules are neutral.
Graphite contains DELOCALISED ELECTRONS that move between the layers and carry charge through the substance, conducting electricity.
What is a dative covalent bond?
Where one atom contributes BOTH electrons to the shared pair.
