3.1 Three types of substances and atomic model

• Scheikunde
• Middelbare school
• havo
• Leerjaar 3

Three types of substances and atomic model

Paragraph 3.1

Learning goals

At the end of the lesson you can:

• predict wether a substance will conduct electrity.
• state the number of protons, electrons and neutrons in an atom.
• describe what isotopes are.

Demo - Conduction

Gallium (solid and liquid)

Zincchloride (solid and liquid)

Tallow (solid and liquid)

Types of substances

Type	Solid	Liquid	Dissolved in water
Metal	yes	yes	-
Molecular substance	no	no	no
Salt	no	yes	yes

Types of substances

Type	Consist of
Metal	metal-atoms
Molecular substance	non-metal atoms
Salt	metal- and non-metal atoms

Atomic model

An atom is composed of protons, neutrons and electrons.
The 1+ charged protons (p) and the neutral neutrons (n) are in the atomic nucleus
The 1− charged electrons (e^-) are in a cloud around the atomic nucleus.

phet.colorado.edu

Number of particles

• atomic number = number of protons
  (determines type of atom)

• number of electrons = number of protons (no charge)
  

• mass number = number of protons + number of neutrons

Isotopes

What type of substance conducts electricity at the solid phase?

1. Metals
2. Salts
3. Molecular substances

What type of substance consists of a metal and a non-metal?

1. Molecular substances
2. Metals
3. Salts

Sodium has atomic number 11 and mass number 24. How many protons does sodium have?

1. 11
2. 13
3. 24
4. 35

Sodium has atomic number 11 and mass number 24. How many electrons does sodium have?

1. 11
2. 13
3. 24
4. 35

Sodium has atomic number 11 and mass number 24. How many neutrons does sodium have?

1. 11
2. 13
3. 24
4. 35

When a neutron joins the nucleus then ...

1. the atom number becomes higher
2. the atom number becomes lower
3. the mass number becomes higher
4. the mass number becomes lower

N-14 has 7 protons and 7 neutrons.
C-14 has 6 protons and 8 neutrons.
N-14 and C-14 are isotopes

1. true
2. false

Making exercise

Make 3+10 (10 min in silence)

Finished? Make 1, 2, 4, 5, 7, 8, 9, 11-15

Reflection

At the end of the lesson you can:

• predict wether a substance will conduct electrity.
• state the number of protons, electrons and neutrons in an atom.
• describe what isotopes are.