Metals
Metals and Non-Metals can be distinguished from one another by their CHEMICAL and PHYSICAL properties.
The video illustrates briefly the physical properties of metal and non-metals.
This video gives a brief overview on the chemical properties of metals.
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Chemical properties and reactions of metals
Metals are elements whose atoms have a SMALL number of valence electrons, usually 1, 2 and 3. They form POSITIVE cations in chemical reactions by LOSING these valence electrons.
Mà Mn+ + n e
Metals form IONIC COMPOUNDS when they react and the metal behaves as a REDUCING AGENT since it give electrons to the other reactant.
Some metals are relatively stable while others react violently when exposed to other substances. The way in which a particular metal reacts gives an indication of its reactivity.
The reactivity of a metal is related to the metal's position in the periodic table.
The following documents look at reactions of certain metals with oxygen, water and dilute acids.
Mà Mn+ + n e
Metals form IONIC COMPOUNDS when they react and the metal behaves as a REDUCING AGENT since it give electrons to the other reactant.
Some metals are relatively stable while others react violently when exposed to other substances. The way in which a particular metal reacts gives an indication of its reactivity.
The reactivity of a metal is related to the metal's position in the periodic table.
The following documents look at reactions of certain metals with oxygen, water and dilute acids.
Reactions of metals with oxygen
reactions_of_metals_with_oxygen.doc | |
File Size: | 39 kb |
File Type: | doc |
If the metal oxides produced in these reactions can dissolve in water, the resulting solution is ALKALINE.
From the reactions with oxygen we see that potassium, sodium, calcium and magnesium are the most reactive metals. These metals are found in Groups I and II of the periodic table, i.e. to the far left of the table. In general, the reactivity of metals decreases from left to right across the periodic table.
From the reactions with oxygen we see that potassium, sodium, calcium and magnesium are the most reactive metals. These metals are found in Groups I and II of the periodic table, i.e. to the far left of the table. In general, the reactivity of metals decreases from left to right across the periodic table.
Reactions of metals with water
reactions_of_metals_with_water.doc | |
File Size: | 34 kb |
File Type: | doc |
Some metals do not react with water. They do, however, react with steam. The fact that they require steam to react means that they are LESS reactive than the ones that react with cold water.
Reactions of metals with dilute acids
reactions_of_metals_with_dilute_acids.doc | |
File Size: | 32 kb |
File Type: | doc |
In general, reactive metals react with acids, except nitric acid, to form a salt and hydrogen gas.
The metals which are very reactive with oxygen and water are also very reactive with acids. The reactions between the metals and dilute sulphuric acid are very similar to the reactions which occur with dilute hydrochloric acid.
The metals which are very reactive with oxygen and water are also very reactive with acids. The reactions between the metals and dilute sulphuric acid are very similar to the reactions which occur with dilute hydrochloric acid.
The Reactivity Series
Based on the reactions above, metals can be placed in order of their reactivities.
The Reactivity Series can be used:
1) As a general guide to the reactivity of a metal.
2) To predict displacement reactions between metals and their salts.
3) To predict the thermal stability of a salt.
4) To determine the most suitable method of extraction of a metal from its ore.
The Reactivity Series can be used:
1) As a general guide to the reactivity of a metal.
2) To predict displacement reactions between metals and their salts.
3) To predict the thermal stability of a salt.
4) To determine the most suitable method of extraction of a metal from its ore.
Extraction of Metals
Metals can be found in nature:
- Uncombined or free. These are limited to metals of VERY LOW reactivity, e.g. silver, gold, copper, platinum and nickel.
- Combined in the form of ores. These include the majority of metals. Chief ores of economic importance are metal oxides, sulphides, chlorides and carbonates.
The method used to extract a metal from its ore is guided by the position of the element on the REACTIVITY SERIES.
- Sodium, Magnesium and Aluminium: Metals high up on the series are strongly bonded in their compounds. Electrolysis is the only method strong enough to extract these.
- Zinc, Iron and Tin: Metals in the middle or the series are less strongly bonded in their compounds. Their oxides can be reduced by carbon to give metal.
- Copper, Silver and Gold: Metals at the bottom of the series can be found uncombined in nature. They simply need to be purified of unwanted materials. When they do occur in ores, e.g. copper sulphide, heating is strong enough to displace the metal from the ore.
TWO widely used metals are IRON and ALUMINIUM. The extraction of these shall be considered in detail.
- Uncombined or free. These are limited to metals of VERY LOW reactivity, e.g. silver, gold, copper, platinum and nickel.
- Combined in the form of ores. These include the majority of metals. Chief ores of economic importance are metal oxides, sulphides, chlorides and carbonates.
The method used to extract a metal from its ore is guided by the position of the element on the REACTIVITY SERIES.
- Sodium, Magnesium and Aluminium: Metals high up on the series are strongly bonded in their compounds. Electrolysis is the only method strong enough to extract these.
- Zinc, Iron and Tin: Metals in the middle or the series are less strongly bonded in their compounds. Their oxides can be reduced by carbon to give metal.
- Copper, Silver and Gold: Metals at the bottom of the series can be found uncombined in nature. They simply need to be purified of unwanted materials. When they do occur in ores, e.g. copper sulphide, heating is strong enough to displace the metal from the ore.
TWO widely used metals are IRON and ALUMINIUM. The extraction of these shall be considered in detail.