ionic bonding

Question 1

define ionic bonding

Answer 1

an electrostatic force of attraction between th oppositely charged ions

Question 2

how is an ionic bond formed?

Answer 2

. when electrons are transferred from a metal to a non-metal forming oppositely charged ions
. metals loose and become positive non-metals gain and become negative

Question 3

describe the structure of NaCl

Answer 3

. giant ionic lattice
.has oppositely charged ions in a giant lattice network
held together by a strong electrostatic forces of attraction between oppositely charged ions

Question 4

what are the properties of ionic compounds

Answer 4

high MP + BP

Question 5

how does ionic charge affect the MP and BP of init compounds?

Answer 5

IONIC CHARGE
-the greater the charge on the ions the stronger the electrostatic forces of attraction between oppositely charged ions
-the greater the energy required to overcome these forces
greater the charge on ions the higher the MP and BP
EG; MgCl>NaCl - Mg2+ 2CL- vs Na+ Cl-

Question 6

what factors affect the melting point of ionic compounds

Answer 6

IONIC CHARGE - greater the charge on ions the higher the MP and BP
IONIC RADIUS - The smaller the ionic radius, the stronger the electrostatic forces of
attraction between the oppositely charged ions, and the higher the melting points.

Question 7

what is an ionic lattice

Answer 7

. in ionic compound millions and millions of ions are packed together in a regular cubic arrangement, joined by ionic bonds
. this from the 3D structure known as an ionic lattice
. the attractive electrostatic forces between the oppositely charged ions are very strong and hold the lattice together.

Question 8

how does ionic radius affect the MP and BP of in it compounds?

Answer 8

The smaller the ionic radius, the stronger the electrostatic forces of attraction between the oppositely charged ions, and the higher the melting points.

Question 9

compare the melting points of the following ionic compounds and arrange them in order of increasing melting points (4 marks)
Na2O, K2O, Rb2O

Answer 9

• all three have the same anion O2-
• they all contain cations from the same group and therefore they all have the same charge 1+
• when going down the group the atomic radius increases
• so as you go down the group the electrostatic forces of attraction between the group 1 cations and the anion would decrease
• therefore less energy is needed to overcome the forces as you move down group one

ion radius Na2O > K2O > Rb2O
Na2O - highest MP Rb2O - lowest MP

Question 10

compare the melting points of the following ionic compounds and arrange them in order of increasing melting points (4 marks)
NaCl, MgCl2, AlCl3

Answer 10

• they share the same anion with the charge 1-
• the cations are in different groups but same period 3
• as you go across period 3 the ionic radius decreases and the charge increases
• there is a strong electrostatic force of
  attraction between the cations of period 3 and the negative chloride ion increases.
• Therefore, more energy is needed to overcome the strong electrostatic forces of
  attraction as you go across the period.
  Ionic charge: Na+ < Mg2+ < Al3+
  Ionic radius: Na+ > Mg2+ > Al3+
  Melting point: NaCl < MgCl2 < AlCl3
  Lowest melting point highest melting point