Particulate nature of matter

Question 1

Ions can be formed in two different ways:

Answer 1

1. Cations are positive ions that are formed when metal atoms give away their valence (outer shell) electrons.
2. Anions are negative ions that are formed when a non-metal atom takes in electrons to fill its valence shell.

Question 2

Why do ions form?

Answer 2

They do this to obtain the noble gas electronic configuration by having a full, or empty, valence (outer) shell.

Question 3

What electronic configuration do metal ions have?

Answer 3

Metal ions have the same electronic configuration as the noble gas, which is at the end of the period above where the metal was.

Example 7: sodium
Sodium is in period 3, so it forms a cation with the noble gas electronic structure of neon, which is in period 2.
sodium = 2.8.1
neon/sodium ion = 2.8

Question 4

What is valency?

Answer 4

Valency is the number of electrons that have been given away, or taken in by an atom. The valency for metals is the same number as the group number in the Periodic table.

Question 5

What electronic configuration do non-metal ions have?

Answer 5

When non-metals atoms form ions they have the noble gas electronic configuration of noble gas in the same period.

Example 8: chlorine
Chlorine in period 3 forms an anion with the same electronic configuration as argon in
period 3.
CHlorine = 2.8.7
argon/chlorine ion = 2.8.8

Question 6

Whats an ionic bond?

Answer 6

An ionic bond is a strong non-directional electrostatic force of attraction between cations
and anions formed due to the transfer of electrons.

Question 7

How is an ionic bond formed?

Answer 7

An ionic bond is formed by a metal atom losing its valence electrons to a non-metal atom
or atoms. The metal ion formed has a positive charge and the non-metal ion formed has a
negative charge. Both ions formed have a noble gas electronic configuration / full outer
shell.

Question 8

The more shells an ion has ___________

Answer 8

the larger the ionic radius

Question 9

When ions form due to the transfer of electrons, they do not exist in pairs, but form __________________

Answer 9

giant 3-dimensional crystal lattice structures with millions of ions arranged in regular rows
with opposite charges next to each other.

• regular arrangement
• alternating positive and negative ions in a 3-dimensional structure.

Question 10

Structure of these giant ionic crystals:

Answer 10

In sodium chloride crystals, each sodium ion is surrounded by 6 chloride ions. Each chloride ion is surrounded by 6 sodium ions forming a giant ionic crystal.

Question 11

How is it held together?

Answer 11

The alternating positive and negative ions in the crystal lattice of ionic compounds are held together by strong non-directional electrostatic forces of attraction.

Question 12

Properties of ions:

Answer 12

1. Conduct electricity when molten or dissolved in solution
2. High melting points and boiling points
3. Soluble in water
4. Brittle

Question 13

Why do ions Conduct electricity when molten or dissolved in solution?

Answer 13

There are mobile ions

Question 14

Why do ions have High melting points and

boiling points?

Answer 14

There are strong non-directional electrostatic forces of

attraction holding the ions together in the giant lattice

Question 15

Why are ions Soluble in water?

Answer 15

Water molecules are able to bond with the positive and

negative ions, which breaks up the lattice and keeps the ions apart

Question 16

Why are ions brittle?

Answer 16

1. If a force is applied to the bottom rows of ions, they move by 1 ion length
2. Then we see that positive ions are lined up with positive ions, and negative ions are lined up with negative ions.
3. We get repulsion between layers and the crystal breaks

Question 17

Define brittle

Answer 17

a solid material that easily breaks into small pieces under force and does not bend.