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The answer to non-ferrous metals: The most common metal is aluminum. Accounting for about 8% of the total weight of the earth's crust, aluminum compounds are found everywhere on the earth, and ordinary soil also contains a lot of aluminum oxide. The lightest metal - lithium. Lithium is only one-fifth the weight of aluminum and one-half the weight of water of the same volume. Lithium not only floats on water, but also in kerosene. The most refractory metal is tungsten. The melting point of tungsten is 3410°C and the boiling point is 5555°C. When the light is on, the temperature of the filament reaches over 3000°C. Only tungsten can withstand such a high temperature. The smallest metal - polonium. The total amount in the earth's crust is minuscule. The most gas-absorbing metal is palladium. At normal temperature, 1 volume of palladium metal can absorb 900-2800 volumes of hydrogen. The most malleable metal element is gold. 1 gram of gold can be drawn into a filament 4,000 meters long ； If beaten into gold foil, the thickness can reach 5×10-4 mm. The most conductive metal element is silver. Its conductivity is 59 times that of mercury. The most expensive metal element is californium. In 1975 the world supplied only about 1 g of californium. The price of a gram is around US$100 million. The most easily applied superconducting element is niobium. When it is cold-sealed to an ultra-low temperature of -263.9°C, it will become a superconductor with almost no electricity. The heaviest metallic element is iridium. Each cubic meter of iridium weighs 22.65 tons. Its specific gravity is about 2 times that of lead and 3 times that of iron (the specific gravity next to iridium is the metal osmium, which weighs 22.16 tons per cubic meter). The hardest metal is sodium. Its Mohs hardness is O. 4. It can be cut with a knife at room temperature. The metal with the lowest melting point is mercury. Its freezing point is -38.7℃. The earliest metal used was copper. According to research, the earliest bronze wares in my country are more than 4,000 years old. Gallium is the metal with the largest liquid range. Its melting point is 29.78℃ and boiling point is 2205℃. The metal most likely to generate electric current when exposed to light is cesium. Its main use is to produce various photoelectric tubes. The metal most sensitive to cold is tin. at temperatures below: At 13.2°C, tin begins to break into powder. When the temperature is lower than -30~-40℃. It will turn into powder immediately. This phenomenon is often called "tin epidemic". The most toxic metal to humans is plutonium. It is 486 million times more lethal than arsenic, and it is also the strongest carcinogen. 1×10-6 grams of plutonium can cause cancer in people. The largest natural gold was discovered by the Star of Hope Gold Mine Company in the Hill End area of Australia on October 19, 1872, weighing 214.3 kilograms. The largest natural silver was found in Sonora, Mexico, weighing 1026.5 kilograms. The purest metal is germanium produced using regional melting technology, with a purity of "Thirteen Nines" (99.99999999999%). The largest amount of radioactive element in seawater is uranium, which is estimated to be 4 billion tons. It is 154.4 times the uranium reserves on land.