Question

Why do metals are found in limited number of colours

Answer 1

When two atoms combine, different types of bonding can occur covalent, ionic, and metallic. Silver, iron, platinum, gold, and copper all form metallic bonds. Unlike covalent bonding, metallic bonding is non-directional. The strong bond consists of positively charged metal atoms in fixed positions, surrounded by delocalized electrons. These delocalized electrons are often referred to as "a sea of electrons," and can help explain why copper and gold are yellow and orange, while most other metals are silver.
The color of metals can be explained by band theory, which assumes that overlapping energy levels form bands.