solid structures

Question 1

sodium chloride (giant ionic)

Answer 1

Composed of oppositely charged ions
Cl- is surrounded by 6 Na+ and Na+ is surrounded by 6 Cl-
6:6 coordination number

Question 2

caesium chloride (giant ionic)

Answer 2

number of oppositely charged surrounding each ion is 8
8:8
(Cs is larger than Na meaning it can hold more ions)

Question 3

properties (giant ionic)

Answer 3

• high melting point/ boling point (large amount of electrostatic energy between bonds= difficult to break)
• electrical insulators until molten when ions are free to move
  -brittle due to repulsion between charges
• some are soluble as the ions can be surrounded by water molecules

Question 4

diamond and graphite (giant covalent)

Answer 4

-two allotropes of carbon
-in diamond each carbon bonds to four others (tetrahedral)
-In graphite each carbon bonds to three others forming hexagonal layers held together by weak van der waal bonds.

Question 5

properties of diamond

Answer 5

-high melting point
-insoluble in water (no charged particles so it cannot interact with the permanent dipoles in water)
-very hard (carbon bonded to four others)
-electrical insulator (no delocalized electrons)

Question 6

properties of graphite

Answer 6

-high melting point
-insoluble in water (no charged particles)
-soft and slippery (layers slide over each other)
-conductive as delocalised electrons are present (only bonds 3 times)

Question 7

simple covalent

Answer 7

lattice structures held together by weak intermolecular forces
covalent bonds within a molecule (e.g iodine,2,)- intramolecular
van der waal occurs between molecules- intermolecular

Question 8

summary of bonds in simple covalent

Answer 8

intramolecular- within a molecules (covalent)
intermolecular- between molecules (van der waal)

Question 9

Why is ice less dense than water

Answer 9

ice forms a tetrahedral shape that is rigid and spaced out, making it less dense
unlike Iodine 2 water has only hydrogen bonds