- Atoms can join together as molecules by forming covalent bonds.
- Covalent bonds are formed when atoms share an electron.
- Another way for atoms to bond is through ionic bonding.
- Ionic bonding occurs when one atom steals an electron from another atom.
- Electrons have a negative charge, so when one is stolen, the thieving atom acquires a negative charge and is called an anion.
- The atom that is stolen from acquires a positive charge and is called a cation.
- Rainfall encounters carbon dioxide and dissolves it, which makes the water acidic.
- Acidic water is able to dissolve mineral salts as it percolates through the bedrock.
- Some water is collected from underground aquifers — this kind of water usually contains a high amount of dissolved mineral salts and is referred to as ‘hard water’.
- Other water is collected from reservoirs — this kind of water usually has a much lower mineral content because it has had less contact with mineral salts. It is referred to as ‘soft water’.
Polar molecule A molecule that has an uneven distribution of electrons between the covalently bonded atoms
Adhesion The measure of how much two substances or surfaces are attracted to each other