Metals can be categorized in many ways based on their chemical and physical properties. Here are some common ways of categorizing metals:
1. Material Classification: Metals can be classified into common and rare metals. Common metals include iron, copper, aluminum, zinc, magnesium, etc., while rare metals such as silver, gold, platinum, titanium, germanium, etc. are less abundant in the earth's crust.
2. Structural classification: Metals can be categorized as crystalline and amorphous based on their crystal structure. Crystalline type metals have a regular crystalline structure with regular arrangement of atoms, such as iron and steel, aluminum, copper, and so on. While amorphous type metals have no obvious crystal structure, such as special alloys, amorphous steel and so on.
3. Grouping of metals: According to the periodic table, metals can be divided into main group metals and transition metals. Main group metals include elements of groups 1, 2 and 13 to 18, such as sodium, aluminum, zinc, lead, etc. Transition metals include elements of groups 3 to 12, such as iron, copper, chromium and nickel.
4. Conductivity Classification: Metals can be classified according to their electrical conductivity. The metals with conductivity higher than 1×10^6 (Ω-m) are known as good conductors, such as silver, copper, gold, etc.; metals with conductivity between 1×10^4 and 1×10^6 (Ω-m) are known as intermediate conductors, such as aluminum, tin, iron, etc.; and the metals with conductivity lower than 1×10^4 (Ω-m) are known as poor conductors, such as zinc, lead, nickel, etc.
These are some of the common ways of categorizing metals, and different ways of categorization can be chosen as needed for better study and application of metallic materials in the field of materials science, chemistry or engineering.