3.3 Molecular substances

• Scheikunde
• Middelbare school
• havo
• Leerjaar 3

Molecular substances

Paragraph 3.3

Learning goals

At the end of the lesson you can:

• State the properties of molecular substances
• Derive the systemic name from the molecular formula and backwards.

Properties molecular substances

Consists of molecules made of non-metal atoms

Have relatively low melting points

Usually don't conduct electricity

Form the largest group of the three types of substances

From molecular formula to name (1)

1. Write down the names of the symbols

2. Write down the Greek numeral for the index of each kind of atom. (mono only with the second atom)

3. Write down the suffix after the last kind of atom

Greek numerals

From molecular formula to name (2)

The name of the last atom changes a bit (-ide):

- chlorine => chloride

- sulphur => sulfide

- oxygen => oxide 

Systematic name

What shows a total number of 6 atoms in a molecule?

1. hexa
2. tri
3. di
4. penta

What is the name of:

1. phosphoruschloride
2. phosphoruspentachloor
3. phosphoruspentachloride
4. pentachloorphosphoride

What is the name of

SiBr​4​​(s)

1. siliciumbromide
2. siliciumtribromide
3. siliciumtetrabromide
4. siliciumpentabromide

Making exercises

Make 34+35+38 (15 min in silence)

Finished? Make 28b,c, 29a,b, 32a,b

Reflection

At the end of the lesson you can:

• State the properties of molecular substances
• Derive the systemic name from the molecular formula and backwards.