Covalent bonding

Question 1

what is covalent bonding

Answer 1

where electron pairs are shared by both the participating atoms

• the shared pair of electrons are localized in a definite space between the nuclei of the two atoms
• covalent bonds are directional and established between atoms of the same or different nonmetallic elements

Question 2

factors favouring covalent bonding

Answer 2

high ionisation  energies 
equal electron affinities 
equal/similar electronegativities 
high nuclear charge 
small atomic size 
number of valence electrons

Question 3

where do the shared pair of electrons spend most of its time

Answer 3

between the two nuclei

Question 4

how is the covalent bond formed

Answer 4

by electrostatic attraction between oppositely charged nuclei and shared electrons

Question 5

how to draw lewis structure

Answer 5

• draw electron configuration of atoms involved
• count valence electrons for all atoms to determine the total number of electrons in the molecule
• use pairs of electrons to form single bonds between atoms
• arrange remaining electrons around atoms to satisfy the octet rule
• if you run out of electrons use multiple bonds to complete octets

Question 6

what is dative covalent bonding

Answer 6

where both the bonding electrons are provided by one of the linked atoms
the atom acting as the donor must have a lone pair of electrons
the atom acting as the acceptor should have a vacant orbital to accept the electron pair donated by the donor

Question 7

how many bonds does a linear shape have, give bond angles and an example

Answer 7

2 bond, bond angles = 180

example BeCl2

Question 8

how many bonds does a trigonal planar shape have, give bond angles and an example

Answer 8

3 bonds, bond angles = 120

example AlCl3

Question 9

how many bonds does a tetrahedral shape have, give bond angles and an example

Answer 9

4 bonds, bond angles = 109.5

example CH4

Question 10

how many bonds does a trigonal bipyramidal shape have, give bond angles and an example

Answer 10

5 bonds, bond angles = 90 and 120

example PCl5

Question 11

how many bonds does an octahedral shape have, give bond angles and an example

Answer 11

6 bonds, bond angle = 90

example SF6

Question 12

how many bonds does a bent linear shape have, give lone pairs

Answer 12

2 bonds 1 lone pair

Question 13

how many bonds does a linear shape have, give lone pairs

Answer 13

1 bond, 2 lone pairs

Question 14

how many bonds does a pyramidal shape have, give lone pairs

Answer 14

3 bonds 1 lone pair

Question 15

how many bonds does a bent linear shape have, give lone pairs

Answer 15

2 bonds 2 lone pairs

Question 16

how many bonds does a linear shape have, give lone pairs

Answer 16

1 bond, 3 lone pairs

Question 17

pure non-polar covalent bond

Answer 17

has no electronegativity difference between two atoms

Question 18

polar covalent bond

Answer 18

has a small electronegativity difference

Question 19

ionic bond

Answer 19

has a large electronegativity difference

Question 20

give 4 examples of giant covalent structures

Answer 20

diamond
silicon dioxide
graphite
carbon nanotube

Question 21

properties of giant covalent structures

Answer 21

contain many atoms 
can be similar to an ionic lattice
properties depend on structure 
silicon and diamond very strong, hard and insoluble in all solvents 
graphite can conduct in one direction