Definition: Atoms or groups of atoms with a net electrical charge.

Types:

Cations: Positively charged ions (e.g., Na+, K+). Formed by losing electrons.

Anions: Negatively charged ions (e.g., Cl-, O2-). Formed by gaining electrons.

Key Points:


Ions are essential for many biological and chemical processes.

Molecular Ions

Definition:

Molecules that have gained or lost electrons, resulting in a net charge.

Types:

Cationic molecular ions: Positively charged (e.g., CH4+, He+, N2+).

Anionic molecular ions: Negatively charged (e.g., O2-, NO-).

Formation: Often formed through processes like ionization in discharge tubes.

Free Radicals

Definition: Atoms or groups of atoms with an unpaired electron.

Characteristics:

Highly reactive due to the unpaired electron.

Often involved in chemical reactions and biological processes.

Formation: Can be generated through homolytic cleavage of bonds, and exposure to heat, or light.


Types of Molecules


Monoatomic:

Consist of a single atom (e.g., He, Ne, Ar).

Diatomic:

Consists of two atoms (e.g., H2, O2, Cl2).

Triatomic:

Consists of three atoms (e.g., H2O, CO2).

Polyatomic:

Consists of more than three atoms (e.g., CH4, H2SO4, C6H12O6).

Homoatomic:

Consists of the same type of atom (e.g., H2, O3, S8).

Heteroatomic:

Consists of different atoms (e.g., CO2, H2O, NH3).

The Mole Concept

Definition:

A unit of measurement for the amount of a substance.

Avogadro's number: 6.02 x 10^23 particles (atoms, molecules, or ions).

Molar mass: The mass of one mole of a substance.

Relationship between mass, moles, and particles:

In summary, ions, molecular ions, and free radicals are important concepts in chemistry. Ions have a net charge due to the gain or loss of electrons, while free radicals have an unpaired electron, making them highly reactive.


Molecules can be classified based on their number of atoms and the types of atoms they contain. The mole concept provides a way to relate the mass of a substance to the number of particles it contains.

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