Bonding

Question 1

Why do bonds form?

Answer 1

To achieve a more stable electron arrangement.

Question 2

What does ionic bonding occur between?

Answer 2

Metals and non-metals.

Question 3

Where are the electrons transferred in an ionic bond and why?

Answer 3

From the metals to the non-metals because metals have few electrons in their outer level so easily lose them.

Question 4

What forces attract the two ions formed from an ionic bond?

Answer 4

Electrostatic forces of attraction between oppositely charged ions.

Question 5

What is the structure called that ionic compounds exist in?

Answer 5

A lattice

Question 6

Name three properties of an ionic compound?

Answer 6

Solids at room temperate, have a high melting point because a lot over energy is required to overcome the forces of attraction between ions. Conduct electricity when molten and are brittle because if positive and positive charges meet they repel.

Question 7

What does a covalent bond form between?

Answer 7

Two non-metals which share a pair of electrons.

Question 8

Why don’t the molecules in a covalent bond have a charge?

Answer 8

No electrons have been transferred.

Question 9

How does the sharing of electrons hold the molecules together?

Answer 9

Electrostatic attraction between the nucleus of the molecule and the shared electrons.

Question 10

How many electrons are shared in a double covalent bond?

Answer 10

4

Question 11

Why can molecules in a covalent bond not conduct electricity?

Answer 11

There are no ion to conduct the charge.

Question 12

What is a coordinate bond?

Answer 12

One in which one atom donates both of the electrons to be shared.

Question 13

Why are metals good conductors of electricity?

Answer 13

Delocalised electrons which can move freely through out the structure.

Question 14

What does the strenth of a metal depend on?

Answer 14

The charge on the ion (more delocalised electrons- stronger the electrostatic attraction) and the size of the ion (smaller - closer to the nucleus - stronger).

Question 15

What is electronegativity?

Answer 15

The power of an atom to attract the electron density in a covalent bond towards itself.

Question 16

What does electronegativity depend on?

Answer 16

The nuclear charge, the distance between the nucleus and the outer electrons and the shielding of nuclear charge by inner electrons.

Question 17

What are the most electronegative atoms?

Answer 17

Nitrogen, oxygen and fluorine.

Question 18

Name three types of intermolecular forces

Answer 18

Van der Waals forces, dipole-dipole and hyfrogen bonding.

Question 19

What do van der Waals forces increase with?

Answer 19

The number of electrons present, so bioling points increase with an increased atomic number or chain length.

Question 20

What conditions need to be present for hydrogen bonding to occur?

Answer 20

A very electronegative atom with a lone pair of electrons covalently bonded to a hydrogen atom.

Question 21

What is electron pair repulsion theory?

Answer 21

Electron pairs will repel other pairs so they take up positions as far away from each other as possible to minimise repulsion.

Question 22

What is enthalpy?

Answer 22

The heat energy change measured under constant pressure.

Question 23

What are the four basic crystal types?

Answer 23

Ionic, metallic, molecular and macromolecular.

Question 24

What are the differences between macromolecular and molecular crystals?

Answer 24

Macromolecular crystals have covalent bonds throughout the compound while in molecular crystals the bonds are between the atoms in the molecule not between molecules. Macromolecular has a much higher boiling point because of this.