Hint:To answer this question, you should recall that It has been observed that matter exists in nature in different forms. Some substances are rigid and have a fixed shape like wood and stone; some substances can flow and take the shape of their container like water, while there are forms of matter that do not have definite shape or size such as air. Thus, the matter can be classified into different categories based on the physical properties exhibited by them and the states in which they exist; these are called states of matter.
We can summarize the features of different states of matter as:
1.In solids, particles are tightly or closely packed.
2.The gaps between the particles are tiny and hence it is tough to compress them.
3.Solid has a fixed shape and volume.
4.Due to its rigid nature, particles in solid can only vibrate about their mean position and cannot move.
4.Force of attraction between particles is adamant.
5.The rate of diffusion in solids is very low.
1.In a liquid state of matter, particles are less tightly packed as compared to solids.
2.Liquids take the shape of the container in which they are kept.
3.Liquids are difficult to compress as particles have less space between them to move.
4.Liquids have fixed volume but no fixed shape.
5.The rate of diffusion in liquids is higher than that of solids.
6.Force of attraction between the particles is weaker than solids.
1.In gases, particles are far apart from each other.
2.Force of attraction between the particles is negligible, and they can move freely.
3.Gases have neither a fixed volume nor a fixed shape.
4.The gaseous state has the highest compressibility as compared to solids and liquids.
5.The rate of diffusion is higher than solids and liquids.
6.The kinetic energy of particles is higher than in solids and liquids.
Hence, a) The general name of rigid form of matter is solids and b) The general name of fluid form of matter is liquids.
You should know about another state of matter known as Plasma. Plasma is a not so generally seen form of matter. Plasma consists of particles with extremely high kinetic energy. Electricity is used to ionize noble gases and make glowing signs, which is essentially plasma.