Olympiad Test: Materials: Metals & Non Metals - UPSC MCQ

Metals generally have 1, 2 or 3 electrons in their outermost orbit or valence shell. e.g.,

The number of valence electrons in sodium, magnesium and aluminium metals are 1, 2 and 3 respectively.

Non-metals generally contain 4,5,6,7 or 8 electrons in their outermost orbit or shell.

The number of valence electrons in carbon, nitrogen, oxygen and fluorine are 4, 5, 6, 7 respectively.

Elements which show the properties of both the metals and non-metals are called metalloids. e.g., antimony and arsenic

Calcium is more reactive than magnesium. Hence, Mg can be replaced from its salt by calcium.

Aluminium foil is prepared by beating it into sheets, i.e., property of malleability. Hence, aluminium foil is used for the given application.

Sulphur is yellow in colour.

Non-metals have low densities, low melting points and are poor conductors of electricity.

Bromine is the only non-metal which exists in liquid state at room temperature.

Copper and mercury metal do not react with dilute hydrochloric acid as they come after hydrogen in the activity series, i.e., they can't replace hydrogen from hydrochloric acid.

Among the given metals, sodium is a highly reactive metal, so it reacts vigorously to form salt and hydrogen. 

2Na+2HCl→2NaCl+H₂↑

Non-metals form two types of oxides, they can be acidic or neutral oxides

Some oxides of non-metals are neutral. e.g., CO.

Phosphorus combines with oxygen and forms two oxides phosphorus trioxide and phosphorus pentoxide.

Acidic oxides dissolve in water and form acids. Sulphur trioxide (SO₃) reacts with water and produces sulphuric acid (H₂SO₄)SO₃+H₂O→H₂SO₄

Silver bromide, a compound of silver is used to make photographic films. When light falls on the film, it sets up a reaction which changes silver bromide to silver 

Crucibles are used in the laboratory to perform high temperature reactions. They should resist high heating (they should not break). For this purpose, a mixture of graphite (an allotrope of carbon) and clay is used to make crucibles.

Sulphur is used in the process of vulcanization. Rubber when treated with sulphur becomes harder than ordinary rubber, so it is used to make tyres.

Gold, silver and platinum do not combine readily with other elements to form compounds, so they are called noble metals.

Sodium has less density, hence it is soft and can be cut even with a knife.

Metal tungsten is used as a filament in electric bulbs because it has a high melting point.