§2.1 Molecules and Atoms (theory)

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

§2.1 Macro and micro level

Chapter 2: Building blocks of substances

Learning Objectives 2.1.

• 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

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.
• giving the systematic names of molecules.
• describing the difference at the micro level between a separation method, a phase transition and a chemical reaction.

Remember the particle model?

 

Chemical Reactions...

Molecules are broken down and new molecules are formed.

A reaction can be written down as an equation or process:

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

 

the 

alphabet 

of 

chemistry

Het alfabet and the PT:

Alphabet	PT
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 

Practise the names and symbols in table 1!

 

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.

Naming compounds - Nomenclature, systematic

1. First element of compound keeps its own name
2. Second element gets -ide at the end 
3. Greek numbering words are used to indicate how many of each element is in the formula

N2O = dinitrogen oxide                      CCl4  = carbon tetrachloride 

  

Greek:	number
mono-	1
di-	2
tri-	3
tetra-	4
penta-	5
hexa	6

hepta-	7
octa-	8

Name: index comes first

Formula: symbol comes first, followed by index

Never start a name with mono

Practise:

Give the name:

1. N2O5

2. P2I4

3. S2Cl2

Give the formula:

1. phosphorous trichloride

2. dinitrogen monoxide

3. diphosphorous pentaoxide