7: Ionic and Metallic Bonds

Question 1

What are the three groups substances can be classified into according to their electrical conductivity?

Answer 1

Conductors, electrolytes, and non-conductors

Question 2

What are the properties of electrical conductors?

Answer 2

They are substances which conduct electricity and are not chemically changed during the conduction process.

Question 3

What are the properties of electrolytes?

Answer 3

They are substances which conduct electricity in molten or aqueous solution but not in solid state, and are decomposed during the conduction process.
Compounds made up of metals and non-metals are electrolytes.

Question 4

What are the properties of electrical non-conductors?

Answer 4

They are substances which do not conduct electricity in solid, molten state, nor aqueous solution.
Compounds made of non-metals are non-conductors.

Question 5

What is an ionic bond?

Answer 5

An ionic bond is the strong electrostatic forces or attraction between oppositely charged ions.

Question 6

How are ionic bonds formed?

Answer 6

Ionic bonds are formed when electron(s) is/are transferred from one atom (or group of atoms) to another (or group of atoms).

Question 7

What are the properties of the arrangement of ions in sodium chloride and why?

Answer 7

The ions are packed together in a regular arrangement called a lattice. This is because ionic bonding is non-directional as each ion in the lattice is attracted to every other with ion with opposite charge.
Sodium chloride has a giant structure as it contains a very large number of ions.

Question 8

What is the definition of polyatomic ions?

Answer 8

Polyatomic ions are ions that are formed by a group of atoms.

Question 9

What is the definition of oxoanion?

Answer 9

An oxoanion is a negative polyatomic ion that contains oxygen.

Question 10

What are the naming patterns for different oxoanions formed by the same element?

Answer 10

Some elements can form two type of oxoanion, each containing a different number of oxygen atoms. The name of the oxoanion with less oxygen atoms ends in “-ite”, while the name of that with more oxygen atoms ends in “-ate”.

Question 11

What are the characteristics on charge and naming of simple ions from the first 20 elements?

Answer 11

A simple/monoatomic ion is derived from a single atom. All simple metal ions and H⁺ ions are cations, while all simple non-metal ions are anions with -ide ending.

Question 12

What are the naming characteristics of polyatomic ions?

Answer 12

A polyatomic ion is derived form a group of ions. Those ending with -ide are simple anions except for OH^- and CN^- (hydroxide and cyanide ion). Those ending with -ite are polyatomic ions with less O atoms, while those ending with -ate are polyatomic ions with more O atoms. The same transition metal can form more than one simple cation with different charges.

Question 13

What are the chemical formulas of hydrogen ion, calcium ion, nitride ion, fluoride ion, and phosphide ion?

Answer 13

Hydrogen ion: H⁺
calcium ion: Ca²⁺
nitride ion: N^3-
fluoride ion: F^-
phosphide ion: P^3-

Question 14

What are the chemical formulas of ammonium ion, silver ion, and zinc ion?

Answer 14

ammonium ion: NH₄⁺
silver ion: Ag⁺
zinc ion: Zn²⁺

Question 15

What are the chemical formulas of nitrate ion, nitrite ion, carbonate ion, and hydrogencarbonate ion?

Answer 15

nitrate ion: NO₃^-
nitrite ion: NO₂^-
carbonate ion: CO₃^2-
hydrogencarbonate ion: HCO₃^-

Question 16

What are the chemical formulas of sulphate ion, sulphite ion,
and hydrogensulphate ion?

Answer 16

sulphate ion: SO₄^2-
sulphite ion: SO₃^2-
hydrogensulphate ion: HSO₄^-

Question 17

What are the chemical formulas of chromate ion, dichromate ion, and phosphate ion?

Answer 17

chromate ion: CrO₄^2-
dichromate ion: Cr₂O₇^2-
phosphate ion: PO₄^3-

Question 18

What are the chemical formulas of permanganate ion, cyanide ion, and hydroxide ion?

Answer 18

permangenate ion: MnO₄^-
cyanide ion: CN^-
hydroxide ion: OH^-

Question 19

What are the colours of chromate ion, dichromate ion, and chromium(III) ion in aqueous solution?

Answer 19

chromate ion: yellow
dichromate ion: orange
chromium(III) ion: green

Question 20

What are the colours of iron(II) ion, iron(III) ion, cobalt(II) ion, and copper(II) ion in aqueous solution?

Answer 20

iron(II) ion: pale green
iron(III) ion: yellow
cobalt(II) ion: pink (cobalt chloride paper)
copper(II) ion: blue

Question 21

What are the colours of manganese(II) ion, permanganate ion, and nickel(II) ion in aqueous solution?

Answer 21

manganese ion: pale pink
permanganate ion: purple
nickel(II) ion: green

Question 22

How can the migration of permanganate ions be observed with an experimental set-up?

Answer 22

1. Add a piece of potassium permanganate crystal onto a piece of filter paper moistened with sodium sulphate solution.
2. Clip the ends of the filter paper and pass electricity through the paper.
3. The purple spot beneath the potassium permanganate crystals migrates to the positive terminal, indicating that the negatively-charged permanganate ions are purple.
4. Colourless potassium ions also migrate to the negative terminal, but they cannot be observed.

Question 23

How can the migration of copper(II) ions and chromate ions be observed with an experimental set-up?

Answer 23

A direct current is passed through a gel containing copper(II) ions and chromate ions. After a few minutes, a blue colour appears at the negative electrode while a yellow colour appears at the positive electrode. This is because the blue copper(II) ions are attracted to the negative electrode, while the yellow chromate ions are attracted to the positive electrode.

Question 24

When observing the migration of copper(II) ions and chromate ions, explain why an orange colour is observed at the positive electrode.

Answer 24

Dichromate ions are orange in colour. When

Question 25

What is a metallic bond?

Answer 25

A metallic bond is the strong electrostatic forces of attraction between the positive metal ions and a “sea” of delocalised electrons.

Question 26

Is metallic bond directional and why?

Answer 26

Metallic bond is non-directional as all the delocalised electrons are attracted to the nuclei of all metal ions in all directions.

Question 27

What are the similarities and differences of atoms and their simple ions?

Answer 27

An atom and its ion have different physical and chemical properties because they have different numbers of electrons, while the identity of an element does not change after gaining or losing electrons as the number of protons stay the same.