BONDING

Question 1

Crystals

Answer 1

crystals are solid held together by force of attraction.

Question 2

forces of attraction includes?

Answer 2

intermolecular forces - london forces, dipole dipole forces and hydrogen bonds.

• bonding - ionic, covalent and metallic bonding.

Question 3

ionic bonding

Answer 3

ionic bonding is the strong electrostatic force of attraction between oppositely charged ions.

Question 4

ionic structure

Answer 4

the ionic structure exists in a lattice ( regular pattern of oppositely charged ions). ions are held together by strong electrostatic force of attraction. eg is sodium chloride.

Question 5

why do ionic compounds have ahigh melting point?

Answer 5

ionic compounds have strong electrostatic attraction between oppositely charged ions. therefore a lot of energy is required to break the strong bonds.

Question 6

why can ionic structures conduct electricity ?

Answer 6

when dissolved in water or molten, ionic lattice break into ions. ions are free to move and able to carry charge which allows ionic structure to conduct electricity in even aqueous or molten state.

Question 7

metallic bonding

Answer 7

metallic bonding is the strong electrostatic attraction between positively charged ions and negatively charged delocalised electrons in a lattice.

Question 8

metal ions

Answer 8

metal ions are held in a regular lattice. example is magnesium.

Question 9

why does metallic bonding have high melting points

Answer 9

becaus eof the strong electrostatic attraction between positive ions and delocalised sea of electrons . the more number of delocalised electrons = the stronger the bonding = the higher the melting point.

Question 10

conductivity in metals

Answer 10

delocalised electrons can pass kinetic energy to each other,making metals good thermal conductors. metals are a good electricty conductor because the delocalised electrons can move and carry current.

Question 11

solubility of metals

Answer 11

metals are insoluble except in some liquids because of the strength of the metallic bonds.

Question 12

covalent bonding

Answer 12

covalent bonding involves strong electrostatic attraction between shared pair of electrons and the nuclei of the bonded atom.
it usually occurs between non metals. and is represented by dot and cross diagrams.

Question 13

why do metals want to have a full shell?

Answer 13

to increase stability and decrease reactivity.

Question 14

single covalent bonding

Answer 14

single covalent bonding involves one shared pair of electrons. example h20 where hydrpgen and oxygen share one pair of shared electrons on both sides leading to a full outer shell.

Question 15

multiple covalent bonding

Answer 15

involves more than one shared pair of electrons. involves double bonds and triple bonds. oxygen is an example of double bond as it shares two shared pairs of electrons to gain a full outer shell and exanple of triple bonds is nitrogen.

Question 16

dative covalent bonds or co ordinate bonds.

Answer 16

one atom donates both of the electrons in a covalent bond. eg ammonium ion or nh4 +.

Question 17

structures of the covalent compounds

Answer 17

1. simple molecular lattice
2. giant covalent latttice.

Question 18

simple molecular lattice

Answer 18

• made up of simple molecules.
• exists as a lattice in solid state.
• atoms held together by strong covalent bonds within molecules.
• weak intermolecular forces of attraction between the molecules.

Question 19

properties

Answer 19

1. low mp and bp = because of the weak intermolecular forces between the molecules.
2. no electrical conductivity because there is no charged particle.
3. only soluble in non polar solvents.

Question 20

giant covalent mplecule

Answer 20

• atoms are joined to adjacent atoms by strong covalent bonds.
• giant lattice is formed.
• example : graphite, diamond and silica

Question 21

properties of giant covalent structures

Answer 21

1.high mp and bp because of the presence of the strong covalent bonds. more energy required to break the bonds.
2. insoluble in polar and non polar solvents because the strong covalent bonds are not disrupted by any solution.
3. no electrical conductivity as there is no charge in the electrons except graphite.

Question 22

exception : graphite

Answer 22

between the layers of lattice, delocalised electrons are able to move when voltage is applied. electrons are able to move freely parallel to the layers.

Question 23

types of giant covalent substance

Answer 23

diamond = high mp, very hard, insoluble and non conductor.
graphite = high mp, soft and slippery, insoluble and electrical conductor.
silica = high mp, hard , insoluble and non conductor.