bonding

Question 1

metallic bonding
structure
bonding
describe

Answer 1

giant metallic lattice
strong metallic bonds
strong electrostatic attraction of positive metal ions surrounded by a see of delocalised electrons

Question 2

compare the strength of the metallic bonds in Mg and Na

Answer 2

Mg has a greater charge of 2+
Mg has twice as many electrons in the sea of delocalised electrons
Mg ions are smaller meaning there is a greater charge density
therefore the attraction between Mg 2+ ions and the delocalised electrons are stronger

Question 3

what are the properties of metals why ?

Answer 3

good thermal/electrical conductors
due to delocalised electrons

strong - strong electrostatic attractions

malleable- layers of metals slide past each other

high mp and bp

Question 4

covalent bonding
structure
bonding
describe

Answer 4

macro molecular/ simple molecular
strong covalent between atoms weak intermolecular forces between the molecules
a covalent bond is a shared pair of electrons between 2 atoms

Question 5

name macromolecular structures

Answer 5

carbon
silicon
silicon oxide

Question 6

name macromolecular crystals

Answer 6

diamond and graphite

Question 7

ionic bonding
structure
bonding
describe

Answer 7

giant ionic lattice
strong ionic bonds
strong electrostatic attraction between oppositely charged ions

Question 8

properties of ionic compounds

Answer 8

high mp /bp
conductive in molten /aqueous
brittle / shatter easily

Question 9

shapes with 3 pairs of electrons involved

Answer 9

triaganol planar 120°
vshaped 117.5°

Question 10

shapes with 4 electron pairs involved

Answer 10

tetrahedral 109.5
prymidal 107 - 1 lone pair
v-shaped 105.5 - 2 lone pair

Question 11

shapes with 5 electron pairs involved

Answer 11

triaganol biprymidal 90° and 120°
seasaw 1 lone pair 89° and 119°
triaganol planar 2 lone pair 120°
linear 3 line pairs 180°

Question 12

shapes with 6 electron pairs involved

Answer 12

octahedral 90°
square prymidal 89° 1 lone pair
square planar 90° 2 lone pairs

Question 13

how does hydrogen bonding arise

Answer 13

very large difference in electro negativity between O-H
creates a dipole
lone pair on oxygen atom strongly attracts partial postive on H atom on another molecule

Question 14

how does permanent dipole dipole bonding arise

Answer 14

difference in electronegativty
dipoles don’t cancel molecule has overall perment dipole
attractive between partial postive on one molecule and partial negative on another

Question 15

how does induced dipole dipole bonding arise

Answer 15

random movements of electrons in one molecule leads to an uneven distribution of electron creating a temporary dipole in one molecule
this induces a dipole in neighbouring molecule the dipoles attract

Question 16

define electronegativty

Answer 16

power of an atom to attract the pair of electrons in a covalent bond

Question 17

general trend in mp/bp across period 3

Answer 17

increase and then decrease as you move across period 3

Question 18

trend in mp
na to mg to al

Answer 18

increases
strength of metallic bonding increases
large spread of charge over a smaller ion leads to stronger metallic bonding

Question 19

why does silicon have the highest mp in period 3

Answer 19

giant macromolecular structure
string covalent bonds
lots of energy required to break them

Question 20

trend in mp
P,S,Cl,Ar

Answer 20

all simple covalent structures
P is a tetrahedral shape P4
S forms S8 rings
Cl is diatomic molecules
Ar

S8>P4>Cl2>Ar

bigger -> smaller
stronger induced -> weaker induced

Question 21

boiling point trend across period 3

Answer 21

same as mp but one exception
Si has highest mp but Al has highest bp
to melt Si requires a lot of energy to break strong covalent bonds and hence a higher temp
once melted relatively little energy is then needed to vaporise it
wereas Al still strong electrostatic attractive between metal ions and delocalised electrons