Metals may be soft or hard. The hardness of metal is the resistance of metal to be scratched. It is measured in moh scale. The metals which are scratched easily are called soft metals. Alkali metals like; Sodium(Na), Potassium (K) and Rubidium (Rb) are soft metals.
Metals which show strong resistance towards scratching are called hard metals. Nickle (Ni), Iron (Fe), Tungsten(W) are hard metals. soft and hard metals can be differentiated with reference to sodium (Na) and iron (Fe) as follows.
