Selina Solutions for Class 7 Chemistry Chapter 6 Metals and Non Metals
Concise Selina Solutions for Class 7 Chemistry Chapter 6 Metals and Non Metals
Metals and Non-metals are different types of materials present around us. Metals (like copper and aluminium) are good conductors of heat and electricity, while non-metals (such as phosphorus and sulfur) are insulators. Except for hydrogen, all elements that form positive ions by losing electrons during chemical reactions are called metals. Thus metals are electropositive elements with relatively low ionization energies. They are characterized by bright luster, hardness, ability to resonate sound and are excellent conductors of heat and electricity. Metals are solids under normal conditions except for Mercury. Ionic bonds form when a non-metal and a metal exchange electrons, while covalent bonds form when electrons are shared between two non-metals. An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
Elements that tend to gain electrons to form anions during chemical reactions are called non-metals. These are electronegative elements with high ionization energies. They are non-lustrous, brittle and poor conductors of heat and electricity (except graphite). Non-metals can be gases, liquids or solids.