Question

Which of the following is a property of non-metals?
A.Low densities
B.Low melting points
C.Poor conductor of electricity
D.All of the above

Answer 1

Hint: Non-metal can be defined as a chemical element that lacks metallic properties and is capable of forming anions. They do so by accepting or gaining electrons. They usually consist of 4, 5, 6 or 7 electrons in their outermost shell.

Complete step by step answer:
According to the physical and chemical properties, chemical elements can be divided into three categories, namely, metals, nonmetals and metalloids. In order to answer this question, we need to have a detailed knowledge about the properties of non-metals and also about the major factors that differentiate them from metals. All metals possess a shiny appearance, i.e., they are lustrous. They have the ability to form alloys by combining with other metals. They are good conductors of heat and electricity and when they react with oxygen, they form metal oxides which are basic in nature. Metalloids on the other hand are metallic-looking brittle solids that are either semiconductors and form amphoteric oxides. If we talk about nonmetals, they have a dull appearance, which can be colored or colorless. They have open structures and they always tend to gain or share electrons when they are made to react with other substances. Most of the non-metals have been found to exist in gaseous state at room temperature, while metals are solids at room temperature.
 The general properties of non-metals can be listed as follows-
The atoms of non-metals have been found to be smaller than those of metals. They exhibit very low or poor thermal and electrical conductivities. This is the most important property that distinguishes non-metals from metals.Most of them are gases at room temperature. This means that they have comparatively lower melting and boiling points at normal temperature and pressure conditions.When compared to metals, the non-metals have relatively lower density.They have high ionization energies and electronegativities. This is attributed towards the fact that they have a strong tendency to attract more electrons towards it.They are non- lustrous because they lack shiny appearance.

So, from the above discussion, we can clearly say that the correct option is D.

Note:
Some of the uses of non-metals can be listed as follows-
-Nitrogen is a non-metal. It is used in the preparation of ammonia, nitric acid and fertilizers
-Chlorine is used for purifying water
-Hydrogen which is used as rocket fuel is also a non-metal.
-Carbon, in its graphite form, finds its use in manufacturing pencils.