What Are The Two Types Of Pure Substances?

Mixtures and pure substances are the two classes in which matter is classified. Substances formed from only one kind of particle are known as pure substances. These types of substances have a fixed structure. They are usually homogeneous and consist of only one kind of atom or molecule. To be precise, these are substances that cannot be separated into two or more substances. As they are homogeneous, their composition remains uniform throughout.

Additionally, these substances have fixed melting and boiling points. These are the substances that participate in chemical reactions to form predictable products. Also, they are classified into two types of substances– 

1. Elements
2. Compounds

Types of pure substances

• Elements

Elements are pure substances that cannot be broken into different atoms, as they only contain one type of atom. Almost 120 elements are known to date, each with unique characteristics. All these elements are arranged in the Periodic table based on their properties. 

Even after using physical or chemical means, an element cannot be broken down. Also, they cannot get transformed into new substances. Some examples of elements are carbon, hydrogen, oxygen, and nitrogen. 

Characteristics of elements

• Homogeneous in nature, elements are pure substances composed of only one kind of atom. 
• Even after using a physical or chemical method like chemical reactions, electricity, or heat, elements cannot be broken down into simpler substances. 
• Atom is the smallest unit of an element. Hence, an element depicts all the properties of its smallest unit.
• The boiling and melting points of elements are fixed.
• Metal, metalloids, and nonmetals are elements. 

• Compounds

Compounds are the types of substances formed by combining two or more elements in a fixed ratio. The atoms of a compound are kept intact by chemical bonds. The bonds structure when molecules share electrons. There are various kinds of chemical bonds, and they fluctuate in how strongly they keep the atoms of a compound intact. Two of the most common types of bonds are covalent and ionic bonds. 

One typical example of a compound is water. One molecule of water is formed when one atom of oxygen reacts with two hydrogen atoms. All these atoms are held together by covalent bonds. 

Properties of compounds

• Homogeneous in nature, compounds are pure substances composed of the same types of molecules.
• Physical methods cannot be used to separate the components of a compound. However, chemical and electrochemical processes can be used to separate them. 
• The composition of the compound is fixed.
• A compound’s properties differ from the properties of its constituent elements. 
• They have fixed melting and boiling points. 

How are compounds different from mixtures?

Same as compounds, a mixture comprises more than one element. However, unlike compounds, mixtures do not have a fixed chemical composition. It means that substances in a mixture are combined in any proportion. A mixture likewise doesn’t include a chemical reaction. Consequently, the substances in a mixture are not changed into other new substances, and they can be isolated from one another without a chemical reaction. 

Similarities between compounds and elements

Any substance consuming volume and mass is known as matter. The subject of Science ascertains substances into different types of substances: Elements, mixtures, and compounds. Strangely, compounds and elements share comparatively more  similarities. At first look, they both might seem different other than that; they are both pure substances. Similarities between the two are as mentioned below:

• Basic unit: atom

Atoms combine to form molecules. Both- compounds and elements are molecules. The former is composed of one type of atom, while the latter consists of two or more kinds of atoms. But, they are both similar concerning their fundamental unit. It means the basic unit of both compounds and elements are atoms. 

• Bonds

The stabilization of atoms is acquired by framing bonds with each other. Correspondingly, compounds and elements exist in a stable structure by forming bonds. The two bonds usually formed between atoms are:

1. Ionic bonds
2. Covalent bonds

Covalent bonds are formed between atoms by sharing electrons, similar to the oxygen elements existing in a stable structure by covalently bonding two oxygen atoms. In contrast, ionic bonds are formed when an electron is lost by one atom to be positively charged. Subsequent atoms acquire the electron to turn out to be negatively charged. Both the negative and positive charges draw in each other to make themselves ionically bonded. Chemical bonding is one other similarity shared between the two kinds of pure substances. 

• Pure substances

Both compounds and elements are types of pure substances that are homogeneous. Therefore, breaking down the two- compounds and elements will give only their constituent atoms and no new substances. 

Conclusion

Pure substances are material that has a fixed composition. To be precise, they are homogeneous. These types of substances have uniform properties throughout. There are two types in which pure substances are classified as – compounds and elements. Elements are substances formed from only one kind of atom. At the same time, compounds are pure substances formed by combining two or more elements in a fixed proportion. Both of the pure substances types share similarities like they both have atoms as their primary unit.