C2 P1: Molecules and atoms

• Scheikunde
• Middelbare school
• havo
• Leerjaar 3

Molecules and atoms lecture  1

Learning objectives 

1. You know that molecules are made up of atoms.
2. You can explain the difference between elements and compounds 
3. You can represent molecules using molecular formula

 Molecules and atoms

in Chemical reactions, the existing substances disappear and new substances arise, with different properties.  

At micro lever, this means that the molecules of the initial substances disappear and new molecules are created of the reaction products. 

Molecules and atoms

Molecules are particles that are in turn made up of even smaller particles: atoms. These atoms in a molecule are connected together by atomic bonds. 

Types of atoms 

There are 118 different types of atoms which are also known as elements. 

All these elements have their own symbols that is made up of one or two letters. 

Molecular formulae

you can represent molecules using a  molecular formula. 

This kind of formula shows how many of which sort of atoms there are in a molecule 

An index is used to indicate how often an atomic type occurs. An index is always located at the bottom right of the atomic symbol. 

Elements and compounds 

With 118 elements you can make millions of different molecules. 

Substances with molecules that consist of just a single type of atom are called elements. 

The concept of an element  therefore has two meanings. 

1. Element is the name of the type of atom. 
2. Element is a substances with molecules that consist of a single type of atom.  

Have No Fear  Of Ice Cold Beer

Elements and compounds 

Molecules that contain more than one type of atom are called compounds. These compounds can arise from reactions between different elements/ atom types. 

The atoms in a molecule are connected together by atomic bonds, during a chemical reaction, these atomic bonds in the molecules are broken and new bonds are formed to make new molecules. The new molecules are a new substance that has different properties at the macro level. 

Compound formulas  

 

Molecules that contain more than one type of atom are called compounds. The molecular formulae of a few well-known compounds are given in the table below. 

Systematic name 

Every compound have their own systematic name which is known worldwide. 

There are three things (rules) to remember when working out the name of a compound.  

1. The type of atom that comes first in the molecular formula simply keeps its own name 

2. the second type of atom in the molecular formula gets the suffix -ide 

3. The systematic name has to count the number of each type of atom in the formula using a Greek-based numbering word. These counting words are places as prefix. 

Homework HT3

Read:  Chapter 2 paragraph 1. Molecules and atoms 

Make: exercise  1,2,4,6 and 7