CHEMISTRY FORM 2
- 1.1 Structure of the atom
- 1.2 Atomic Number and Mass Number
- 1.3 Isotopes
- 1.4 Energy levels and electron arrangement
- 1.5 Development of the Periodic Table
- 1.6 Relative Atomic Mass and Isotopes
- 1.7 Ion Formation
- 1.8 Chemical Formulae
- 1.9 Chemical Equations
- 2.1 Alkali metals (Group I elements)
- 2.2 Alkali Earth Metals (Group II elements)
- 2.3 Halogens (Group VII elements)
- 2.4 Noble gases (Group VIII elements)
- 2.5 Properties and Trends Across the Periodic Table
- 3.1 Bond
- 3.2 Ionic bond
- 3.3 Giant ionic structure
- 3.4 Covalent bond
- 3.5 Co-ordinate bond
- 3.6 Molecular structures
- 3.7 Giant covalent structures
- 3.8 Metallic Bond
- 3.9 Types of bond across a period
- 3.10 Oxides of elements in Period 3
- 3.11 Chlorides of Period 3 elements
- 4.1 What is a salt?
- 4.2 Types of salt
- 4.3 Solubility of salts in water
- 4.4 Methods of preparing salts
- 4.4.1 Reacting a Metal with an Acid
- 4.4.2 Reacting an Acid with a Base (Neutralization)
- 4.4.3 Reacting an Acid with a Carbonate (or hydrogencarbonate of metal)
- 4.4.4 Combining elements Directly (Direct Combination of elements)
- 4.4.5 Precipitation (Double decomposition)
- 4.5 Action of heat on salts
- 4.6 Uses of salts
- 5.1 Electrical conduction
- 5.2 Electrical conductivity of molten substances
- 5.3 Electrical conductivity of substances in aqueous state
- 5.4 Electrolysis
- 5.5 Applications of electrolysis
- 6.1 Allotropes of carbon
- 6.2 Chemical properties of carbon
- 6.3 Carbon (IV) oxide
- 6.4 Carbon (II) oxide (CO)
- 6.5 Large scale production of sodium carbonate and sodium hydrogencarbonate
- 6.6 Effect of carbon (II) oxide and carbon (IV) oxide on the environment
- 6.7 Carbon cycle
Structure of the Atom, and the Periodic Table: Structure of the atom
1.0 Structure of the Atom, and the Periodic Table
1.1 Structure of the atom
Previously, we defined an atom as the smallest particle (of an element) that can take part in a chemical reaction. Although it is the smallest, an atom also has parts, called sub-atomic particles, just like a cell in living things also has parts.
What is a structure?
Parts of an object and the way they are arranged in the object make up a structure. Examples of a structure are classroom with floor, walls, desks, and roof as its parts; a bicycle wheel with the rim, spokes and hub as parts; merry-go-round, and the solar system (the image below).
Structure of the atom
An atom consists of protons, neutrons and electrons as sub-atomic particles. Protons and neutrons occupy the centre, called the nucleus, while electrons are some distance away from the nucleus.
Protons are positively (+) charged, neutrons are neutral (0 electrical charge) and electrons are negatively (-) charged. Protons and neutrons are called nucleons, because they are in the nucleus.
Is the symbol,, familiar? This is a basic symbol of science. It represents movement of electrons around the nucleus, similar to the movement of planets around the Sun, or rim around the hub. But it is a three-dimensional drawing which is rather complex. We will use simplified two-dimensional drawings (Figure 1.1.1).
Figure 1.1.1: Atomic structure
A proton may be represented by p, or +; neutron by n or o, and electron by e, -, dot, or cross (x).
- Name three (3) particles found in an atom.
- What are nucleons?
- Describe the arrangement of sub-atomic particles in an atom.
Answers to Questions 1.1