Question

Complete the following table:

Object/Material	Appearance(Shiny/Dull)	Hardness(Very hard/Not very hard)
Iron
Coal
Sulphur
Aluminium
Copper

Answer 1

Hint: Both appearance and hardness depends on different characteristics of an element. Appearance comes under the trait of lustrous nature of an element. Hardness is the result of the increased forces between the atoms of the elements. Metals are generally lustrous while non-metals are not lustrous.

Complete step by step solution:
-The elements in the periodic table are classified as metals, nonmetals and metalloids. They are classified both on the basis of variations in their physical as well as chemical properties.
-Metals are the elements which lose their electrons to achieve noble electronic configurations and convert themselves into cations. They have very less electronegativity and generally belong to groups 1, 2 and 3.
-Non-metals are the elements which gain their electrons to achieve noble electronic configurations and convert themselves into anions. They have very high electronegativity and generally belong to groups 15, 16 and 17.
-Metalloids are the elements which have their characteristics that lie between that of a metal and a nonmetal. They are very few in number. Only 5 metalloids are present in the periodic table which are Ge, Se, As, Sb and Te.
-The elements given in the options can be distinguished between the metals and the non-metals and from that knowledge, we can comment on the appearance and the hardness of the elements and finally complete the table.
-In the given table, coal and sulphur are non-metals while other elements are metals. Coal is a form of carbon itself and so it belongs to the category of non-metals. The non-metals given are p-block elements while the metals given are d-block elements.
-The metals show d-d transitions in them as they belong to d-block. Due to these transitions, they appear bright in nature and are generally coloured as they absorb some of the visible light spectrum and reflect some other part. So they are lustrous and hence shiny.
-There are no transitions of such sort in non-metals. They gain electrons and complete their octet and so they do not release photons when energy is supplied to them. So, the energy is not reflected and the elements appear dull.
-Metals are hard in nature and so can be broken into sheets or drawn into wires. Non-metals are not hard in nature and so they are neither ductile or malleable.
Therefore the table can be completed as:

Object/Material	Appearance(Shiny/Dull)	Hardness(Very hard/Not very hard)
Iron	Shiny	Very hard
Coal	Dull	Not very hard
Sulphur	Dull	Not very hard
Aluminium	Shiny	Very hard
Copper	Shiny	Very hard

Note: Due to the mentioned properties of metals, they are used in industries for the construction of machines, automobile parts, satellites, cooking utensils, etc. Non-metals cannot be used for that purpose as they are not hard and break down on beating.