covalent bonding

Question 1

what is a covalent bond?

Answer 1

caused by the electrostatic attraction between the bonding shared pair of electrons and the two nuclei

Question 2

why do giant atomic structures like diamond and graphite have high melting points?

Answer 2

contain many strong covalent bonds in a macromolecular structure. it takes a lot of energy to break the many strong bonds

Question 3

what’s a key note of electron density in a covalent compound?

Answer 3

in a covalent compound, there is significant electron density between the atoms

Question 4

what is the effect of multiple bonds on bond strength and length?

Answer 4

nuclei joined by multiple (e.g. double, triple) bonds have a greater electron density between them. this causes a greater force of attraction between the nuclei and the electrons between them, resulting in a shorter bond length and greater bond strength

Question 5

dative covalent bond

Answer 5

forms when the shared pair of electrons in the covalent bond comes from only one of the bonding atoms

Question 6

when can a dative bond form?

Answer 6

only happens if you have a lone pair of electrons are able to be donated

Question 7

what does the direction of the arrow show?

Answer 7

direction of the arrow goes from the atom that is providing the lone pair to the atom that is deficient

Question 8

how to find the shape of a compound

Answer 8

1. number of electrons around central atoms (outer electrons)
2. number of bonds around the central atom
3. +1 for every negative charge
4. -1 for every positive charge
5. divide answer by 2 (number of total electron pairs and then split into lone and bond pairs)

Question 9

what is the bond angle, number of electron pairs and examples of linear?

Answer 9

2 bonding pairs, 0 lone pairs
180 degrees
e.g. CO2, CS2, HCN, BeF2

Question 10

what is the bond angle, number of electron pairs and examples of trigonal planar?

Answer 10

3 bonding pairs, 0 lone pairs
120 degrees
e.g. BF3, AlCL3, SO3, NO3-, CO3 2-

Question 11

what is the bond angle, number of electron pairs and examples of tetrahderal?

Answer 11

4 bonding pairs, 0 lone pairs
109.5 degrees
e.g. SiCL4, SO4 2-, ClO4-, NH4+

Question 12

what is the bond angle, number of electron pairs and examples of trigonal pyramidal?

Answer 12

3 bonding pairs, 1 lone pair
107 degrees
e.g. NCl3, PF3, ClO3, H3O+

Question 13

what is the bond angle, number of electron pairs and examples of bent?

Answer 13

2 bonding pairs, 2 lone pairs
104.5 degrees
OCl2, H2S, OF2, SCl2

Question 14

what is the bond angle, number of electron pairs and examples of trigonal bipyramidal?

Answer 14

5 bonding pairs, 0 lone pairs
120 and 90 degrees
e.g. PCl5

Question 15

what is the bond angle, number of electron pairs and examples of octahedral?

Answer 15

6 bonding pairs, 0 lone pairs
90 degrees
e.g. SF6

Question 16

how do you explain the shape?

Answer 16

1. state the no. of bonding pairs and lone pairs of electrons
2. state that electron pairs repel and try to get as far away as possible
3. if there are no lone pairs state the electron pairs repel equally
4. if there are lone pairs of electrons then state that lone pairs repel more than bonding pairs
5. state actual shape and bond angle

Question 17

why do lone pairs repel more than bonding pairs?

Answer 17

lone pairs are closer into the central atom

Question 18

how much do you reduce the bond angles of lone pairs by?

Answer 18

2.5