I/GCSE Chemistry Question Analysis Topic: Chemistry - Chapter 1: Principles of Chemistry - Ionic Bonding (Part 1)
For I/GCSE Chemistry, you should know:
Let's tackle a new sub-topic of IGCSE Chemistry Chapter 1 - the sub-topic on ionic bonding.
Ionic bonding is a type of chemical bond that arises from the electrostatic attraction between oppositely charged ions. Ions are formed when atoms either lose or gain electrons, becoming positively or negatively charged, respectively.
When atoms lose electrons, they become positively charged ions, called cations. This is common for metallic elements, as they have a tendency to lose their outermost valence electrons to attain a more stable electron configuration. The charges of cations formed by metals in groups 1, 2, and 3 are:
- Group 1 (alkali metals): +1 charge, e.g., Na+, K+
- Group 2 (alkaline earth metals): +2 charge, e.g., Mg2+, Ca2+
- Group 3 (other metals): +3 charge, e.g., Al3+
When atoms gain electrons, they become negatively charged ions, called anions. This is common for non-metallic elements, as they have a tendency to gain electrons to attain a more stable electron configuration. The charges of anions formed by non-metals in groups 5, 6, and 7 are:
- Group 5 (pnictogens): -3 charge, e.g., N3-
- Group 6 (chalcogens): -2 charge, e.g., O2-, S2-
- Group 7 (halogens): -1 charge, e.g., F-, Cl-, Br-, I-
Other common ions and their charges include:
- Ag+: Silver ion
- Cu2+: Copper(II) ion
- Fe2+: Iron(II) ion
- Fe3+: Iron(III) ion
- Pb2+: Lead(II) ion
- Zn2+: Zinc ion
- H+: Hydrogen ion
- OH-: Hydroxide ion
- NH4+: Ammonium ion
- CO3^2-: Carbonate ion
- NO3-: Nitrate ion
- SO4^2-: Sulfate ion
When oppositely charged ions come together, they form ionic compounds held together by ionic bonds. The formula for an ionic compound is determined by the charges of the ions involved, with the objective of achieving overall electrical neutrality. For example:
- Sodium chloride (NaCl): Formed from Na+ and Cl-
- Magnesium oxide (MgO): Formed from Mg2+ and O2-
- Aluminum sulfate (Al2(SO4)3): Formed from Al3+ and SO4^2-
The formation of ionic compounds through the transfer of electrons and the resulting electrostatic attraction between oppositely charged ions is the essence of ionic bonding.
Work hard for your I/GCSE Chemistry examination!
End of analysis. Great!
