Non-metals

This note gives us information about non- metals, differences between metals and non-metals, metalloids and alloys.

Summary

This note gives us information about non- metals, differences between metals and non-metals, metalloids and alloys.

Things to Remember

Metals, when struck with a hammer emit a peculiar sound called metallic clink.
They can be beaten into thin plate except antimony, arsenic and bismuth. Such property is known as malleability.
Wire can be made from metals. Such property is known as ductility.
The elements that show the properties of both metals and non-metals are called metalloids.
An alloy is defined as a homogenous mixture of two or more metals and non-metals.
Non- metals are bad conductor of heat and electricity.
The hardest and most precious non- metal is diamond.

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Non-metals

Non- Metals

Non- metals are the bad conductor of heat and electricity. They are found mostly in the gaseous form. Some of the examples of non- metals are elements like hydrogen, nitrogen, oxygen, phosphorous, chlorine etc. They are electronegative in nature. Non- metals are found in earth's crust and atmosphere. The human body also contains non- metals. The hardest and most precious non- metal is a diamond. Some of the properties of non- metals are given below,

Properties of Metals

Physical properties

They are bad conductors of heat and electricity except graphite.
They are non- malleable.
They are non- ductile.
They have low melting point and boiling point.
They are found in all three state i.e.solid, liquid and gas.
They are transparent and do not have metallic lusture except graphite and diamond.
They are soft. (except diamond)
Non- metals are not sonorous.

Chemical Properties

Oxides of non- metals are either acidic or neutral in nature.
They behave as oxidizing agents.
They react with hydrogen to produce covalent compounds.
They have a tendency to receive electrons.

Comparison between metals and non- metals

S.N	Properties	Metals	Non-metals
1	State	All, except mercury, metals are solid at ordinary temperature.	Non-metals are found in all three states at ordinary temperature.
2	Metallic lusture	They possess metallic luster when they are freshly cut. Except lithium.	Non-metals except Iodine and graphite, do not possess any metallic luster.
3	Hardness	They are generally hard because the molecules are closely packed in them.	They are generally soft in nature except diamond.
4	Breakability	They are hardly broken into pieces.	They can be easily broken.
5	Melting and boiling point	The melting and boiling points of metals are generally high.	They have usually low melting and boiling points.
6	Metallic clink	Metals, when struck with a hammer emit a peculiar sound called metallic clink.	They do not emit any metallic sound.
7	Malleability	They can be beaten into thin plate except antimony, arsenic, and bismuth. Such property is known as malleability.	They are non-malleable.
8	Ductility	Wire can be made from metals. Such property is known as ductility.	They are non-ductile.
9	Conductivity	They are generally good conductors of heat and electricity.	They are poor conductors of heat and electricity except graphite.
10	Specific gravity	They have high specific gravity except Li, Na, K, Ca etc.	They have low specific gravity except diamond.
11	Electrochemical behavior	They form cations or electropositive ions by the loss of electrons.	They form anions or electronegative ions by the gain of electrons.
12	Alloy formation	Metals have the dissolving power to the other metals to form a homogenous mixture.	They generally do not form alloys.
13	Reaction with oxygen	Metals forms basic oxides.	Non-metals form an acidic oxide.
14	Reaction with hydrogen	Metals rarely combines with hydrogen to form unstable hydrides.	Non-metals usually combine with hydrogen to give stable hydrides.
15	Reaction with acids	Most of the metals reacts with dilute acids to form salts and hydrogen.	Usually non-metals do not form salts.

Metalloids

The elements that show the properties of both metals and non-metals are called metalloids. Examples of metalloids are arsenic, antimony and germanium.

Metalloids possess the following characteristics:

They are a poor conductor of heat and electricity.
They possess metallic luster.
They form alloys.
They are neither malleable nor ductile.

Alloys

An alloy is defined as a homogeneous mixture of two or more metals and non-metals. For example, brass is an alloy of copper and zinc.

Alloys have the following properties:

Generally alloys are harder than their components.
They are good conductors of heat and electricity.
They have low melting point.
Alloys increase the strength of metals.
They are malleable and ductile.

Lesson

Metals

Subject

Science

Grade

Grade 9

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