EVERYDAY SCIENCE

Detailed explanation-1: -The hardness of a substance depends on the nature and strength of the bonds that bind the atoms, molecules or ions in a crystal lattice. Three-dimensional covalent network solids such as diamond and silicon are hard and brittle because the bonds holding the crystal together are quite strong.

Detailed explanation-2: -Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and super hard materials, which can be contrasted with soft matter.

Detailed explanation-3: -Molecular hardness can be calculated using atomic ionization energy and electron affinity values through the new method. The agreement was obtained with experimental data.

Detailed explanation-4: -Stronger bonds between atoms make them more difficult to separate and, in general, stronger chemical bonds result in greater hardness, higher melting and boiling points, and smaller coefficients of expansion.

Detailed explanation-5: -PHYSICAL PROPERTIES OF MINERALS Strong chemical bonds give high hardness. Covalently bonded minerals are generally harder than ionically bonded minerals. Cleavage is poor if bond strength in the crystal structure is high and is good of the bond strength is low. Covalent bonds generally produce poor or no cleavage.