Matter is defined as anything that occupies space and has mass.
- This means that it has volume and mass
Matter is made up of very tiny discrete particles (something like building blocks of matter). The particles can be atoms, ions or molecules.
- Atom is the smallest particle of an element. No net charge.
- Ion is an atom or a group of atoms carrying an electric charge.
- Molecule is a group of two or more atoms chemically joined together.
Matter can be divided into two groups – Elements and compounds:
- Element is a substance that contains only one type of atoms and it cannot be broken down to any simpler substance.
- Compound is a substance that is made up of two or more elements chemically joined together.
Two common types of compounds: Ionic compounds and covalent compounds:
- Ionic compound is a combination of metallic and non-metallic elements. The particles in ionic compound are ions.
- Covalent compound is a combination of non-metallic elements. The particles in covalent compound are ions.
State Of Matter
The three most common physical states that matter can exist: Solid, Liquid and Gas.
| Solid | Liquid | Gas | |
|---|---|---|---|
| Shape | Fixed | Not fixed &Take shape of container | Not fixed &Take shape of container |
| Volume | Fixed | Fixed | Not fixed &same as vol. of container |
| Density | High | Moderate | Low |
| Can be compressed? | Cannot be compressed | Cannot be compressed | Can be compressed |
For convenience, state symbols can be used to show the state of a substance:
- Solid: (s)
- Liquid: (l)
- Gas: (g)
- Aqueous: (aq) $\rightarrow$ Mainly used for compounds dissolved in solution.
what is thd diference between molecule and a compound?
A molecule is formed when two or more atoms join together chemically.
A compound is a molecule that contains at least two different elements.
All compounds are molecules but not all molecules are compounds.