Metals and Non-metals Test - 14

Metals are shiny when cut, scratched, or polished; Metals are lustrous, malleable, ductile, good conductors of heat and electricity. Metals are Solid at room temperature except mercury.

Alkali metals are the most reactive metals and, along with the elements in group 17, are the most reactive of all elements.

Zinc is extracted from the purified zinc sulfate solution by electrowinning, which is a specialized form of electrolysis. The process works by passing an electric current through the solution in a series of cells.

Smelting is a process of applying heat to ore in order to extract a base metal.

The cations, positive ions, flow toward the cathode to replace the cations that are being picked up at the electrode. The anions, negative ions, flow toward the anode to balance the positive charge of the cations that are released from the electrode.

Metals are shiny when cut, scratched, or polished; Metals are lustrous, malleable, ductile, good conductors of heat and electricity. Dullness property is generally not shown by metals.

Malleability is a typical property of metals; Malleability is said to be the property of a material to deform under compression. The metals having malleable property can be rolled or beaten into sheets. Malleability is the quality of something that can be shaped into something else without breaking, like the malleability of clay.

The surface of lumps of silicon is protected by a very thin layer of silicon dioxide, SiO₂. This renders silicon more or less inert to further oxidation by air even up to about 900°C. After this, reaction with oxygen in the air gives silicon dioxide.

A mixture is formed by combining two or more materials. A homogeneous mixture appears uniform, regardless of where you sample it Examples of homogeneous mixtures include air, saline solution, most alloys, and bitumen. Alloys such as steel and bronze are homogeneous mixtures of two metals.

Metals like aluminum, zinc, iron do not react with hot/cold water; they react only with steam to form a metal oxide and hydrogen.

Explanations:

Copper does not react with dilute sulphuric acid as its reduction potential is higher than that of hydrogen. Copper does not displace hydrogen from non-oxidising acids like HCl or dilute H₂SO₄.

So, no reaction takes place when dilute sulphuric acid is poured on a copper plate. But when concentrated sulphuric acid is poured over copper plate, effervescence is observed. This happens because of formation of hydrogen gas.