Chemistry - Bonding, Structure and Properties

What is Metallic Bonding?

When metal atoms bond together.

What attraction takes place in metallic bonding?

Positively charged ions and negatively charged delocalised electrons.

Delocalised electrons are not bound to..

an atom and are free to move around within lattice.

Why does delocalisation happen?

Metal atoms have a smaller number of electrons in there outer shell.

Why do metallic properties conduct electricity?

The delocalised electrons carry electrical charge through the structure.

Why do metallic properties conduct heat?

the delocalised electrons and closely packed ions transfer energy through the structure by conduction.

Are metallic properties malleable and ductile?

Yes

Why do metallic properties have high melting and boiling points?

large amounts of energy are needed to break the strong metallic bonds in melting/boiling.

Why do the melting and boiling points increase as you move across the periodic table?

A stronger bond.

What is an Ion?

A charged particle that has a different number of protons and electrons.

What is a positive ion?

has more protons (+) than electrons (-)

What is a negatively charged ion?

has more electrons (-) than protons (+)

What is Ionic Bonding?

The bonding between metal and non-metal atoms

In Ionic Bonding a metal atom transfers electrons to a..

non - metal atom, allowing both of them (the metal and non-metal) to have a full outer shell

group 1 and 2 metals always..

loose electrons resulting in a positive charge.

group 6 and 7 non metals always..

gain electrons resulting in a negative charge.

Why do Ionic properties have high melting and boiling points?

Due to the strength of the electrostatic forces between the ions.

Why do Ionic properties conduct electricity when dissolved or molten?

Only then are the ions free to move around to carry the charge.

What is covalent bonding?

The bonding between two metal atoms

Covalent bonds are formed when..

2 non-metal atoms share pairs of electrons.

Why are covalent bonds strong?

The shared electrons are attracted to the nucleus of both atoms.

Covalently bonded substances can be..

• small molecules (e.g. water)

• large molecules (e.g. polyester and silk)

• giant covalent structures (e.g. diamond)

Why do covalent properties have a low melting and boiling point?

due to the weak intermolecular forces between the molecules.

Why don’t covalent properties conduct electricity?

No free electrons to carry the electrical current.

Each carbon in diamond are bonded to..

4 other carbon

Each carbon in graphite are bonded to..

3 other carbon

Does diamond conduct electricity?

No

Does graphite conduct electricity?

Yes

What are intramolecular bonds?

Covalent bonds, which are very strong.

What are intermolecular forces?

Between small molecules are very weak and easy to break.

What are small molecules?

Individual small molecules are held together by intramolecular bonds. Numerous small molecules can be held together by intermolecular forces.

What form are small molecules usually in?

Liquid or gas at room temperature.

Small molecules don’t contain delocalised electrons, due to this..

they cannot conduct electricity.

Do small molecules have low melting and boiling points?

Yes

Bigger molecules attract..

Other molecules with stronger intermolecular forces.

Do bigger molecules have a higher boiling and melting point than smaller molecules?

Yes

Can bigger molecules conduct electricity?

No as they don’t contain delocalised electrons.