Bonding, Structure and Properties of Matter (pgs 112 - 121)

Question 1

How do metal atoms form ions?

Answer 1

They lose electrons to form positive ions

Question 2

If an atom loses 3 electrons, what will be the charge on the ion formed?

Answer 2

3+

Question 3

Explain why elements in the same group usually form ions with the same charge?

Answer 3

They have the same number of outer electrons, so have to lose or gain the same number of electrons to get a full outer shell

Question 4

What charge do sulfur (group 6) ions have?

Answer 4

2-

Question 5

Ionic bonding occurs between what types of element?

Answer 5

Metals and non-metals

Question 6

How does an ionic bond form?

Answer 6

A metal atom loses electrons to form a positively charged ion. These electrons are gained by a non-metal atom, which forms a negatively charged ion. These oppositely charged ions are attracted to each other by electrostatic forces. (this is the ionic bond)

Question 7

Describe the electron transfer that takes place when calcium (a group 2 metal) and chlorine (a group 7 non-metal) react to form calcium chloride (CaCl2)?

Answer 7

Each calcium atom loses its two outer electrons to form a Ca2+ ion. Two chlorine atoms gain ONE of these electrons each to form TWO Cl- ions

Question 8

List two disadvantages of using dot and cross diagrams?

Answer 8

Any two from:

They don’t show the structure of the compound.

They don’t show the sizes of the ions

They don’t show how the ions are arranged in the compound

They make it look like the electrons shown by crosses are different from the electrons shown by dots

Question 9

Give one advantage of using 3D models over Ball and Stick models to draw Giant Ionic Structures?

Answer 9

3D models allow you to show the sizes of the different ions compared to each other

Question 10

Explain why Ionic compounds conduct electricity when dissolved in water?

Answer 10

The ions separate and can move freely in the solution, allowing them to carry an electric charge.

Question 11

Define the term ‘covalent bond’?

Answer 11

shared pair of electtrons between two non-metal atoms

Question 12

True or false. Atoms can share electrons in any of their shells. Explain your answer?

Answer 12

False.

Atoms can only share electrons in their outer shell

Question 13

How many extra electrons does an atom gain for each single covalent bond it forms?

Answer 13

One extra shared electron

Question 14

This diagram shows the structure of propane. What is the molecular formlar?

  H    H    H
   l       l      l H - C -   C  - C - -H
  l       l      l
 H     H     H

Answer 14

C3H8

Question 15

How many pairs of electrons are shared between the two oxygen atoms in an oxygen molecule?

Answer 15

Two Pairs

Question 16

Give two physical properties of simple molecular substances?

Answer 16

Any two from:

they have very low melting/boiling points, they don’t conduct electricity

Question 17

As simple molecules get bigger, what happens to the intermolecular forces between them?

Answer 17

They get stronger

Question 18

In the displayed formular of a polymer, what does the ‘n’ represent?

  H      H
  l         l (  - C   -   C   - )
  l         l
  H       H          n

Answer 18

n is a large number showing that the unit is repeated a lot of times

Question 19

Explain why most polymers are solid at room temperature?

Answer 19

Polymers are very large molecules and so the intermolecular forces between the molecules are strong. This means that a lot of energy is needed to separate the molecules

Question 20

What type of bond is found between the two Nitrogen atoms in a nitrogen molecule?

Answer 20

a Triple covalent bond

Question 21

Which has a higher melting point, polymers or giant covalent structures? Explain why?

Answer 21

Giant covalent structures. More energy is needed to break the covalent bonds between the atoms in giant covalent structures, than to break the intermolecular forces between polymer molecules.

Question 22

Why can’t diamond conduct electricity?

Answer 22

It doesn’t have any free electrons or ions to carry a charge

Question 23

Why is graphite soft and slippery?

Answer 23

Graphite contains layers of carbon atoms. There are no covalent bonds between these layers, so they are free to move over each other.

Question 24

How is grapite simlar to metals?

Answer 24

Each carbon atom has one delocalised electron that is free to move throughout the structure. This means that graphite can conduct electricity and thermal energy (heat)

Question 25

Give one practical use of nanotubes?

Answer 25

Any one from:

In electronic
To strengthen materials

Question 26

What makes metals good conductors of electricity and heat?

Answer 26

The electrons in the outer shell of the metal atoms are delocalised and free to move around. These electrons can carry electric charge and thermal (heat) energy throughout the whole structure.

Question 27

The layers of atoms in a metal can slide over each other. What property does this give metals?

Answer 27

Metals can be bent or formed into different shapes (they are malleable)

Question 28

Which state of matter has a fixed volume but does not keep a fixed shape?

Answer 28

Liquid

Question 29

How do the particles in a solid behave?

Answer 29

There are strong forces of attraction between particles. The particles are held close together in fixed positions to form a regular pattern with a fixed shape and volume.

Question 30

Give one drawback of the particle theory model

Answer 30

Any one from:

Particles aren’t solid, inelastic spheres - they’re atoms, ions or molecules.

It doesn’t consider the forces between the particles, so you don’t know how strong they are

Question 31

What state symbol would you use for a substance that is dissolved in water?

Answer 31

(aq)

Question 32

Explain how the strength of the forces between particles can result in a substance having a low melting point?

Answer 32

The weaker the forces between particles, the less energy is needed to break them, and so the lower the melting point.

Question 33

What state will a substance be in at a temperature below its melting point?

Answer 33

Solid