There are two types of pure substances first is element second one iscompound

Pure Substances

A pure substance is a form of matter that has a uniform and definite composition. It consists of a single type of particle with specific properties. Pure substances can be classified into two main types: elements and compounds.

1. Elements

Elements are the simplest form of pure substances. They cannot be broken down into simpler substances by chemical means. Each element is made up of atoms, which are the smallest units of matter that retain the properties of the element. There are 118 known elements, with each having its own unique set of properties.

Elements can be further classified into two groups:

- Metallic Elements: Metallic elements are typically shiny, malleable, and good conductors of heat and electricity. Examples include iron, copper, gold, and silver.

- Non-Metallic Elements: Non-metallic elements can be solid, liquid, or gas at room temperature. They are generally poor conductors of heat and electricity. Examples include hydrogen, oxygen, carbon, and nitrogen.

2. Compounds

Compounds are pure substances composed of two or more different elements chemically bonded together in fixed proportions. Unlike mixtures, compounds have a specific chemical formula and consistent properties. The properties of a compound are different from the properties of its constituent elements.

Compounds can be further classified into two groups:

- Molecular Compounds: Molecular compounds are formed by the sharing of electrons between atoms, creating covalent bonds. They have discrete molecules as their basic units. Examples include water (H2O), carbon dioxide (CO2), and methane (CH4).

- Ionic Compounds: Ionic compounds are formed by the transfer of electrons from one atom to another, resulting in the formation of ions. These ions are held together by strong electrostatic forces called ionic bonds. Examples include sodium chloride (NaCl), calcium carbonate (CaCO3), and magnesium oxide (MgO).

Key Points:
- Pure substances are forms of matter with a uniform and definite composition.
- Elements are the simplest form of pure substances and cannot be broken down into simpler substances.
- Compounds are pure substances composed of two or more different elements chemically bonded together.
- Metallic elements are shiny, malleable, and good conductors of heat and electricity.
- Non-metallic elements can be solid, liquid, or gas and are generally poor conductors.
- Molecular compounds have covalent bonds and discrete molecules as their basic units.
- Ionic compounds are formed by the transfer of electrons and have ions held together by ionic bonds.