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Among sodium, magnesium, aluminum, copper, bronze, lead, and zinc, which one has the highest melting point? Which is the lowest? Which are better conductors? Which ones are available in Australia?

1. Silver-white cubic structure metal. The new cut surface has a silvery white luster, which turns to dark gray when oxidized in the air. It is soft and light, with a smaller density than water. It hardens at -20°C and reacts violently with water to generate sodium hydroxide and hydrogen and generate a large amount of heat, which may lead to spontaneous combustion or explosion. In the air, it burns with a bright yellow flame. It will also react when encountering ethanol, reacting with the hydroxyl group of ethanol to generate hydrogen and sodium ethoxide, while releasing heat. Can directly combine with halogens and phosphorus. It can reduce many oxides to their elemental state and can also reduce metal chlorides. When dissolved in liquid ammonia, it forms a blue solution. Heating in ammonia generates sodium amide. Dissolves in mercury to form sodium amalgam. Relative density (H2O)0.968. Melting point 97.82℃. Boiling point 881.4℃. Corrosive.

Conductivity: 20-200

(25C_+1C)uS/cm

2. Discovery process In 1808, David of England used potassium reduction White magnesium oxide (magnesium oxide MgO) was the first to produce a small amount of magnesium. Physical properties: Silver-white metal, density 1.738 g/cm3, melting point 648.9°C. Boiling point 1090℃. Valence +2, ionization energy 7.646 electron volts, it is one of the light metals and has ductility. Metal magnesium is non-magnetic and has good heat dissipation.

Thermal conductivity: 156 W/(m·K )

3.

Silver white light metal. It has ductility and malleability. Products are often made into rods, sheets, foils, powders, ribbons and filaments. In humid air, an oxide film can be formed to prevent metal corrosion. Aluminum powder and aluminum foil can burn violently when heated in the air and emit dazzling white flames. Easily soluble in dilute sulfuric acid, nitric acid, hydrochloric acid, sodium hydroxide and potassium hydroxide solutions, but insoluble in water. Relative density 2.70. Melting point 660℃. Boiling point 2327℃. The content of aluminum in the earth's crust ranks third after oxygen and silicon. It is the most abundant metal element in the earth's crust. The development of the three important industries of aviation, construction, and automobiles requires material properties with the unique properties of aluminum and its alloys, which greatly facilitates the production and application of this new aluminum metal. Application is extremely wide.

Thermal conductivity W/(m·K): 237

4.

Copper is a chemical element, and its chemical symbol is Cu (Latin Phrase: Cuprum), its atomic number is 29, is a transition metal. Copper is a purple-red shiny metal with a density of 8.92 grams/cubic centimeter. The melting point is 1083.4±0.2℃ and the boiling point is 2567℃. Common valences are +1 and +2. Ionization energy 7.726 electron volts. Copper is one of the earliest metals discovered by humans and one of the best pure metals. It is slightly harder, extremely tough and wear-resistant. Also has good ductility. Good thermal and electrical conductivity. Copper and some of its alloys have good corrosion resistance and are very stable in dry air. But in humid air, a layer of green basic copper carbonate Cu2(OH)2CO3 can be generated on its surface, which is called patina. Soluble in nitric acid and hot concentrated sulfuric acid, slightly soluble in hydrochloric acid. Easily corroded by alkali.

Electrical conductivity: ranked 2nd

5.

Bronze originally referred to copper-tin alloy. Later, copper alloys other than brass and cupronickel were called bronze. And the bronze name is often preceded by the name of the first major added element. Tin bronze has good casting properties, good friction reduction properties and good mechanical properties, and is suitable for manufacturing bearings, worm gears, gears, etc. Lead bronze is a widely used bearing material in modern engines and grinding machines. Aluminum bronze has high strength, good wear resistance and corrosion resistance, and is used to cast high-load gears, bushings, marine propellers, etc. Beryllium bronze and phosphor bronze have high elastic limit and good electrical conductivity, and are suitable for manufacturing precision springs and electrical contact components. Beryllium bronze is also used to manufacture non-sparking tools used in coal mines, oil depots, etc.

6.

Lead is a bluish silver-white heavy metal with a melting point of 327.502°C, a boiling point of 1740°C, a density of 11.3437 g/cm3, a hardness of 1.5, a soft texture, and resistance to The tensile strength is small.

Lead without oxide layer has bright color, high density, very low hardness and strong extensibility. Its electrical conductivity is quite low and its corrosion resistance is high, so it is often used as a container for highly corrosive substances (such as sulfuric acid). Adding a small amount of antimony or other metals can further improve its corrosion resistance.

Metal lead is exposed to oxygen, water and carbon dioxide in the air, and its surface will quickly oxidize to form a protective film;

7. Zinc is a blue-white metal. The density is 7.14 g/cm3 and the melting point is 419.5°C. At room temperature, it is brittle; at 100 to 150°C, it becomes soft; after exceeding 200°C, it becomes brittle again. The chemical properties of zinc are active. In the air at room temperature, a thin and dense basic zinc carbonate film is formed on the surface, which can prevent further oxidation. When the temperature reaches 225°C, zinc oxidizes intensely. When burning, it emits a blue-green flame. Zinc is easily soluble in acid and can easily replace gold, silver, copper, etc. from the solution. Zinc mostly exists in the sulfide state in nature. The main zinc-containing mineral is sphalerite. There are also small amounts of oxidized minerals such as smithsonite, smithsonite and hemimorphite.

Electrical conductivity 16.6×106/(m·Ω)

There is no bronze in Australia

Use bronze to make sculptures. For details, see Bronze Properties