Chemical Bonding.

Question 1

What is chemical bonding?

Answer 1

The joining, chemically of two or more atoms to form a compound.

Question 2

What is an ion?

Answer 2

An ion is an electrically charged atom or group of atoms formed by the loss or gain of electrons.

Question 3

Why would an atom loses or gain electrons in the outermost shell?

Answer 3

This loss or gain of electrons takes place to gain a full outer shell of electrons.

Question 4

Ionisation of metals and non-metals:

Answer 4

Metals: all metals lose electrons to other atoms to become positively charged ions.

Non-metals: all non-metals gain electrons from other atoms to become negatively charged ions.

Question 5

What holds the positive and negative charges of ionic compounds together?

Answer 5

The positive and negative charges are held together by the strong electrostatic forces of attraction between opposite charges.

Question 6

What is an ionic bond?

Answer 6

An ionic bond is the electrostatic force of attraction between positive and negative ions.

Question 7

What happens when an atom loses an electron?

Answer 7

When an atom loses an electron it forms positively charged ions called cations.

Question 8

What happens when an atom gains electrons?

Answer 8

When an atoms gains electrons it forms negatively charged ions called anions.

Question 9

What is a lattice structure?

Answer 9

A regular arrangement of alternating positive and negative ions.

Question 10

How do you describe the forces of attraction between the positive and negative ions of a giant lattice structure?

Answer 10

The forces of attraction between the positive and negative ions of a giant lattice structure are very strong.

Question 11

What are the 3 physical properties of ionic compounds?

Answer 11

• Ionic compounds have high melting and boiling points.
• Ionic compounds are soluble in water but insoluble in organic solvents.
• Ionic compounds conduct electricity only when molten or when dissolved in water because the ions are mobile.

Question 12

Why do Ionic compounds have a high melting and boiling point?

Answer 12

Because a lot of heat energy is required to break the strong force of attraction..

Question 13

Why are ionic compounds soluble in water but not organic solvents?

Answer 13

They are soluble in water because the water molecules are able to separate the ions from one another and keep the ions in solution.

Question 14

When are covalent compounds formed?

Answer 14

Covalent compounds are formed when electrons are shared between atoms.

Question 15

What are the properties of covalent compounds?

Answer 15

• Covalent compounds have low melting points and boiling points because the intermolecular attractive forces are weak.
• Covalent compounds are insoluble in water but can dissolve in organic substances.
• Covalent compounds do not conduct electricity because they have no free electrons or ions.

Question 16

What are the allotropes of carbon?

Answer 16

Diamond and graphite are allotropes of carbon that have giant covalent structures.

Question 17

What are the three properties of diamonds?

Answer 17

• Diamond does not conduct electricity
• Diamond has very high melting and boiling point.
• Diamond is extremely hard and dense

Question 18

What is diamond used in?

Answer 18

Diamond is used in jewellery and as cutting tools.

Question 19

In a diamond, how is a giant tetrahedron covalent structure formed?

Answer 19

Each carbon atom bonds with four other carbons, forming a tetrahedron.

Question 20

What are the three properties of graphite?

Answer 20

• Graphite conducts electricity.
• Graphite has a very high melting point.
• Graphite is soft and slippery.

Question 21

What are the covalent bonds of a diamond like.

Answer 21

All the covalent bonds in diamonds are identical and strong with no weak intermolecular forces.

Question 22

Why does graphite conduct electricity?

Answer 22

The free electrons that exist in between the layers and are free to move and carry charge, hence graphite can conduct electricity.

Question 23

In graphite, how is a giant hexagonal covalent structure formed?

Answer 23

Each carbon atom is bonded to three others forming layers of hexagonal-shaped forms, leaving one free electron per carbon atom.

Question 24

Why is graphite slippery and smooth?

Answer 24

The covalent bonds within the layers are very strong but the layers are connected to each other by weak intermolecular forces, hence the layers can slide over each other making graphite slippery and smooth.

Question 25

What is graphite used for?

Answer 25

Graphite is used in pencils, industrial lubricants and is also used to make carbon electrodes for electrolysis.

Question 26

Why do diamond and silicon (IV) oxide not conduct electricity?

Answer 26

Diamond and silicon (IV) oxide do not conduct electricity because all its valence electrons are used in bonding - no free electrons.

Question 27

In silicon (IV) oxide or silicon dioxide, how is a giant tetrahedron covalent structure formed?

Answer 27

A tetrahedron is formed because each silicon atom is bonded to four oxygen atoms but each oxygen atom is bonded to only two silicon atoms.

Question 28

What does silicon (IV) oxide or silicon dioxide or SiO2 naturally occur as?

Answer 28

SiO2 is a macromolecular compound that occurs naturally as sand and quartz.

Question 29

What are the 4 properties of silicon (IV) oxide?

Answer 29

• Silicon (IV) oxide is very hard.
• Silicon (IV) oxide has very high melting and boiling points.
• Silicon (IV) oxide does not conduct electricity.
• Silicon (IV) oxide has lots of very strong covalent bonds and no intermolecular forces.

Question 30

What is metallic bonding?

Answer 30

The electrostatic force of attraction between positive metal ions and a sea of delocalized electrons.

Question 31

Why are metallic bonds strong?

Answer 31

Metallic bonds are strong because of the attraction between the positive metal ions and the negatively charged delocalized electrons.

Question 32

What are the 3 properties of metals?

Answer 32

• Metals have high melting and boiling points.
• Metals are good thermal and electric conductors.
• Metals are malleable(can be hammered into shape) and ductile (can be drawn into a wire).
• Metals are lustrous.
• Metals are sonorous.

Question 33

Why do metals have a high melting and boiling point?

Answer 33

There are many strong metallic bonds in giant metallic structures therefore a lot of heat energy is needed to overcome forces and break these bonds.

Question 34

Why are metals good conductors of electricity?

Answer 34

Metals can conduct electricity because the sea of delocalized electrons is able to move.

Question 35

Why are metals, good thermal conductors?

Answer 35

Conduction of heat is due to vibrations of the atoms passing on the energy from one atom to the next.

Question 36

Why are metals malleable and ductile?

Answer 36

The regular arrangement of metal ions means that the layers of ions are able to slide over each other easily without the metal shattering, making metals malleable and ductile.

Question 37

Practical studying:

Answer 37

• Drawing Ionic Bonds.
• Drawing Covalent Bonds.
• Metallic Bonds.

Question 38

Metal + non-metal bonding =

Answer 38

Metal + non-metal = ionic bond.

Question 39

Non-metal + non-metal bonding =

Answer 39

Non-metal + non-metal = covalent.

Question 40

Metal + metal bonding =

Answer 40

Metal + metal = metallic.

Question 41

What is an alloy?

Answer 41

An alloy is a mixture of two or more elements , where at least one element is a metal

Question 42

What are the four properties of non-metals?

Answer 42

• Non-metals are dull.
• Non-metals are poor conductors of electricity and heat.
• Non-metals are brittle.
• Non-metals have a low boiling and melting point.