§2.1 Molecules and Atoms / §2.2 The Periodic Table

• Scheikunde
• Middelbare school
• havo, vwo
• Leerjaar 3

§2.1 Macro and micro level

§2.2 The Periodic Table

Chapter 2: Building blocks of substances

Learning Objectives 2.1 / 2.2:

• What the macro level and the micro level is
• That most substances consist of molecules
• What the different phases look like on a micro level
• Difference at the micro level between pure substances and mixtures
• Why models are needed in chemistry
• That molecules consist of atoms
• The most important kinds of atoms and their symbols
• Metals and noble gases do not consist of molecules, but only of atoms

Perspective on learning objectives by

• knowing that molecules are made up of atoms.
• explaining the difference between elements and compounds.
• representing molecules using molecular formulae.
• describing the difference at the micro level between a separation method, a phase transition and a chemical reaction.

Remember the particle model?

 

Chemical Reactions...(explained from macro to micro level)

• Properties of substance change
• Molecules (substances) are broken down and new kind of molecules
   (substances) are formed.
• A rearrangement of atoms from reactants  into new products

Finally a reaction can be written down as an equation or process:

molecules go in (reactants), different molecules come out (products).

 

Atoms as

building 

blocks

The 

alphabet 

of 

chemistry

The alphabet compared to the Periodic Table:

Alphabet	Periodic Table
Letter	Atom/Element
Word	Molecule
Sentence	Substance
Story	Materials

Atoms in a molecule are connected by atomic bonds (bonds between atoms)

Elements in the periodic table

We know about 118 different kinds of atoms, aka 118 elements

Every element has its own name and symbol 

Practice the names and symbols
using the Periodic Table

 

d

Elements

Based on one kind of atom or molecules with one kind of atom (pure)

ggg

g

Compounds

Molecules containing more than one kind of atom.

Molecules can be drawn but they can also be given a molecular formula.

Phase transitions

Solid to liquid = Melting

Liquid to solid = Freezing

Liquid to gas = Evaporation

Gas to liquid = Condensation

Gas to solid = Deposition

Solid to gas = Sublimation

Solid

- Fixed shape (crystal)

- Molecules are vibrating

- Not a lot of kinetic energy

         (Low temperature)

Liquid

- No fixed shape, Volume fixed

- More space between molecules and they shake a lot more (more kinetic energy)

- Medium kinetic energy

           (medium temperature)

Gas

- No fixed shape, no fixed volume

- Distance between molecules is big

- Velocity of molecules is high, Kinetic energy is high