Chemistry SPM: Learn Formation of Ions in 4 minutes (Basic with illustration) in SPM!

Описание: 5.2 Ionic Bond    • Chemistry SPM: Learn Formation of Ions in ...  
5.3 Covalent Bond    • Chemistry SPM: Learn Covalent Bond in 5 Mi...  
5.4 – 5.6 Hydrogen bond, Dative Bond, Metallic Bond    • Chemistry SPM: Hydrogen, Dative and  Metal...  
5.7 Properties of Ionic and Covalent compounds    • Chemistry SPM: Physical Properties of Ioni...  

Ions are formed when atoms lose or gain electrons in order to fulfill the octet rule and have full outer valence electron shells. When they lose electrons, they become positively charged and are named cations. When they gain electrons, they are negatively charged and are named anions.
When an atom loses or gains electrons, the number of electrons no longer equals the number of protons.
It is therefore no longer electrically neutral – it is now charged.
An atom that has become charged by gaining or losing electrons is called an ion.
Atoms that form ions gain or lose the number of electrons that result in them have full valence shells.
For most atoms, a full valence shell consists of eight electrons.
For the smallest atoms and ions (hydrogen, helium, lithium and beryllium), a full valence shell consists of two electrons.
When an atom loses electrons, it forms a positive ion.
This is because there are now more positively charged protons than negatively charged electrons.
A positive ion is also called a cation.
When an atom gains electrons, it forms a negative ion.
This is because there are now more negatively charged electrons than positively charged protons.
A negative ion is also called an anion.
Examples given are: