Covalent Substances Flashcards Preview

Chemistry - Lizzie > Covalent Substances > Flashcards

Flashcards in Covalent Substances Deck (10):
1

Covalent bonding is...

A strong attraction between the bonding pair of electrons and the nuclei of the atoms involved in the bond.

2

What are substances with simple molecular structures?

Gases, liquids, or solids with low melting points.

3

Simple molecular substances, melting and boiling points are...

Low, weak intermolecular forces that can be overcome easily.

4

Giant covalent lattices, melting and boiling points are...

High, strong covalent bonds between the atoms in the lattice that require large amounts of energy to break.

5

Why does graphite conduct electricity but not diamond?

• Graphite has a free fourth electron on the outer layer of each atom, which can move around, allowing the graphite to conduct electricity (used for electrodes). • None of the electrons are free to move around, because the atoms are tightly held in covalent bonds (used for insulating material).

6

Why is graphite used for a lubricant and pencil lead but diamond is used for cutting tools and drills?

• Each carbon atom only forms three covalent bonds, creating layers which are free to slide over each other. • Diamond is the hardest material known - there are very strong carbon-carbon covalent bonds which extend throughout the whole crystal in three dimensions. Each carbon atoms forms four covalent bonds in a very rigid structure.

7

Are the melting points of graphite and diamond high or low?

Both very high. • Graphite has strong bonds within the structure which require lots of energy to break. • Diamond has very strong carbon-carbon covalent bonds, which extend throughout the whole crystal in 3D.

8

How does a covalent bond form?

A pair of electrons are shared between two atoms. Only between non-metals.

9

What does the structure of diamond look like?

A image thumb
10

What does the structure of graphite look like?

A image thumb