§3.2 Metals and salts

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• Middelbare school
• havo, vwo
• Leerjaar 3

§3.2 Metals and salts

Chapter 3: The structure of substances

In which group in the PT can you find the element nickel?

Fluorine is in group 17 in the PT.
What is the name of this group?

1. noble gases
2. halogens
3. alkali earth metals
4. metalloids

Which of these atoms have the same atomic number?

1. All three
2. 1 and 2 only
3. 1 and 3 only
4. 2 and 3 only

Why do we call atoms 'neutral´ ?

1. because they contain the same number of electrons and neutrons
2. because they contain the same number of protons and electrons
3. because they contain the same numbers of protons and neutrons
4. because they don't contain charged particles

The nucleus of an atom contains 9 protons and 10 neutrons.
Which statement is correct?

1. The atomic mass is 9 g.
2. The atomic mass is 9 u.
3. The atomic mass is 19 g.
4. The atomic mass is 19 u.

Learning Objectives

1. You can classify substances as metals, salts and molecular based on their atomic composition.

2. You can describe metals at the macro and micro levels.

3. You can describe salts at the macro and micro level.  

Statement:
All substances are made of molecules

1. True
2. False
3. ...what are molecules again?

Properties of metals (macro-level):

All metals...

• are shiny when polished
• can be reshaped  (at high temperatures)
• conduct heat and electricity
• are solid at room temperature (except mercury (Hg)
• they have high melting and boiling points

Metals (at the micro-level)

• Metals are elements (so not compounds, not molecules)
• They consist of positively charged metal atoms (called ions) with free electrons moving between between them. 
• Strong attraction (metallic bonding)
• Electricity and heat conductivity of the metal 

lattice follows from these free flowing electrons. 

§3.2 Metals and salts

Chapter 3: The structure of substances

All materials are made

of atoms:

3.1: Atomic Structure (ALL elements look like this on

The atomic number = p⁺

The mass number =

p⁺ + n⁰

In a neutral atom: 

p⁺ = e^-

Atomic structure:

Metals (at the micro-level)

• Metals are elements (so not compounds, not molecules)
• They consist of positively charged metal atoms (called ions) with free electrons moving between between them. 
• Strong attraction (metallic bonding)
• Electricity and heat conductivity of the metal 

lattice follows from these free flowing electrons. 

Ions vs. atoms:

Metals like to lose one or more electrons

Non metals like to take in one or more electrons

Example: 

Li --> Li+ + 1e-

F + 1e- --> F-

Text

Practice:

1. Draw a sodium atom (with its protons, neutrons and electrons) and draw a sodium ion (Na⁺)

2. How many protons and electrons does a magnesium ion Mg²⁺ contain? 

3. How many protons, neutrons and electrons are present in a ³⁵Cl^- ion?

Answer Q 2

Magnesium has atomic number 12, so the number of protons is 12.

The charge is 2+ so it has (12-2) 10 elektronen (it has given away 2 electrons)

Answer Q 3

Cl has atomic number 17

Protons = 17

Mass number = 35

Neutrons = 18

Charge is -1 so there must be (17 + 1) 18 electrons

Salts

Solids salts are composed of metal and non-metal

ions. 

An ion is an atom with a charge. 

Ions form when an atom is losing or gaining electrons 

(and the number of p⁺ is not equal to the number of e^-)

Examples: 

Kitchen salt consists of Na+ and Cl- ions

Lime stone consists of  Ca2+ CO32-(carbonate) ions

d

d

Metals

• Solid at room temperature (except Hg)
• Positively charged atoms (ions) surrounded by moving electrons
• Metallic bonding
• Metallic lattice
• Conduct electricity in their solid AND liquid state.

Salts

• Salts are solids at room temperature
• Consist of positive metal ions and negative non-metal ions
• Ionic bonding
• Ionic lattice
• Conduct electricity in the liquid state (and in solution)

Comparison between metals and salts

d

d

Page 124, question 2, 3, 6 and 7

Practice

Alloys