Flashcards in Covalent Bonding Deck (15):
What is covalent bonding ?
Is the sharing of electrons between atoms .Occurs in non-metals where electrons are shared between atoms .This is known as covalent bonding .
How is a covalent bond formed ?
Its formed when an electron is shared between atoms and come from the top of the energy level of atom and electrons .
They are held together by weaker intermolecular forces between the molecules .Water molecular are held together by weak intermolecular forces between molecules
What can single covalent bonds be represented by ?
By dot and cross models showing outer shells .
Why does covalent bond occur ?
This is because of less energy is required to share electrons than needed for theses atoms to form ions .
What is dative covalent bonding ?
This is a type of covalent bond where both of shared electrons come from the same atom .Dative covalent bonds are exactly the same in lengths' /strengths as other covalent bonds .
The only difference is that shared pair of electrons come form same atom .
Look at the diagrams
What is bond length ?
its the average distance between the nuclei atoms in a molecule
What is the bond energy ?
This is the energy needed to break a bond .
What is bond length determined by ?
Its determined by the energy of interaction between atoms changes with distance between nuclei .
What do single bonds have ?
They have a greater length than double bonds and double bonds have a greater length than the triple bonds
What about the short length ?
The shorter length of the bond the stronger the bonds is therefore triple bond a stronger than double or single bonds .A single bond between carbon atoms has a length of 154 pm and a bond energy of 347 kj mo1 -1 .
Double bond between carbon atoms
has a length of 134 pm and bond energy of 612 kJ mo1 -1 .
Triple bond between atoms
Bond length of 120 pm and a bond energy of 820kJ mo1-1
An example of dative BOND
An ammonium ions contains a dative bond .When an ammonia reacts with hydrochloric acid , a hydrogen ion from the acid is transferred to the ammonium molecule .A lone pair of electrons on the nitrogen atoms forms a dative covalent bond with the hydrogen ion .