Metals and nonmetals play an essential role in our daily lives. We cannot live without nonmetals such as oxygen, and we would struggle to survive if metals did not exist. What is the chemistry underlying these substances? Let’s learn more about metals and nonmetals’ chemical characteristics.
In a chemical reaction, the chemical property is a characteristic of a substance that can be observed. A chemical reaction is a process in which one substance changes to another substance. Chemical properties are observed as the characteristics of the substances change during this process. There are six important chemical properties of metals, that are given below:
Reaction of Metals with Oxygen
Metals form their respective metal oxides when reacting with oxygen.
Metal + Oxygen → Metal Oxide
The intensity of a reaction of metal with oxygen depends on the chemical reactivity of the metal. Some metals react with oxygen even at room temperature, some react on heating, whereas some metals react on strong heating.
Some examples are given below:
- Reaction of Sodium with Oxygen: Sodium metal reacts with oxygen at room temperature to form sodium oxide.
4Na + O2 → 2Na2O
(Sodium) (Oxygen) (Sodium oxide)
- Reaction of Potassium with Oxygen: Potassium metal reacts with oxygen at room temperature to form potassium oxide.
4K + O2 → 2K2O
(Potassium) (Oxygen) (Potassium oxide)
Since potassium metal and sodium metal are highly reactive and react with oxygen at room temperature so they are stored under kerosene oil to prevent their reaction with the oxygen, moisture and carbon dioxide of air.
- Reaction of Lithium with Oxygen: Lithium oxide is formed when lithium metal reacts with oxygen.
4Li + O2 → 2Li2O
(Lithium) (Oxygen) (Lithium oxide)
Lithium, potassium, sodium, etc. are called alkali-metals. Alkali metals react vigorously with oxygen.
- Reaction of Magnesium with Oxygen: At room temperature, magnesium metal does not react with oxygen. But on heating magnesium metal burns in the air giving intense light and heat to form magnesium oxide.
2Mg + O2 → 2MgO
(Magnesium) (Oxygen) (Magnesium oxide)
- Reaction of Aluminium with oxygen: Aluminium metal reacts with oxygen on heating, to form aluminium oxide.
2Al + 3O2 → 2Al2O
(Aluminium) (Oxygen) (Aluminium oxide)
- Reaction of Zinc with Oxygen: Zinc metal reacts with oxygen only on strong heating to form zinc oxide.
2Zn + O2 → 2ZnO
(Zinc) (Oxygen) (Zinc oxide)
- Reaction of Copper with Oxygen: Copper metal does not react with oxygen even on strong heating. Copper reacts with oxygen on prolonged heating to form a black substance which is called copper oxide.
2Cu + O2 → 2CuO
(Copper) (Oxygen) (Copper (II) oxide)
Other metals like silver and gold metals do not react with oxygen even at high temperatures.
Reaction of Metals with Water
Metal hydroxides and hydrogen gas are formed when metals react with water.
Metal + Water → Metal hydroxide + Hydrogen
However, all metals do not react with water. The intensity of the reaction of metal with water depends on its chemical reactivity. Some metals react with cold water, some react with hot water, some react with steam whereas others do not even react with steam.
Some examples are given below:
- Reaction of Sodium with water: Sodium metal reacts violently with cold water to form sodium hydroxide and hydrogen gas along with a lot of heat.
2Na + 2H2O → 2NaOH + H2
(Sodium) (Water) (Sodium Hydroxide) (Hydrogen)
- Reaction of Potassium with water: Potassium metal reacts violently with cold water to form potassium hydroxide and hydrogen gas along with a lot of heat.
2K + 2H2O → 2KOH + H2
(Potassium) (Water) (Potassium Hydroxide) (Hydrogen)
- Reaction of Calcium with water: Calcium metal reacts with cold water to form calcium hydroxide and hydrogen gas and the heat produced in this reaction is less which is not sufficient to burn the hydrogen gas which is formed.
Ca + 2H2O → Ca(OH)2 + H2
(Calcium) (Water) (Calcium Hydroxide) (Hydrogen)
- Reaction of Magnesium with water: Magnesium metal does not react with cold water. Magnesium metal reacts with hot water to form magnesium hydroxide and hydrogen gas.
Mg + 2H2O → Mg(OH)2 + H2
(Magnesium) (Water) (Magnesium Hydroxide) (Hydrogen)
Magnesium reacts very rapidly with steam. Magnesium becomes magnesium oxide and hydrogen gas when it reacts with steam. Metals like aluminium, zinc and iron do not react with either cold water or hot water. These metals react with steam to form metal oxide and hydrogen.
- Reaction of Aluminium with water: Aluminium metal reacts with steam to form aluminium oxide and hydrogen gas.
2Al + 3H2O → Al2O3 + 3H2
(Aluminium) (Steam) (Aluminium oxide) (Hydrogen)
Because of a thin but tough layer of aluminium oxide on its surface, aluminium metal does not react with water under normal conditions.
- Reaction of Zinc with water: Zinc metal produces zinc oxide and hydrogen gas when steam is passed over it.
Zn + H2O → ZnO + H2
(Zinc) (Steam) (Zinc oxide) (Hydrogen)
- Reaction of Iron with water: Iron forms iron oxide and hydrogen gas when it reacts with steam. When iron reacts with moisture in the air, it generates rust (iron oxide).
3Fe + 4H2O → Fe3O4 + 4H2
(Iron) (Steam) (Iron (III) oxide) (Hydrogen)
Other metals, on the other hand, either do not react with water or do so extremely slowly. Steam does not react with lead, copper, silver, or gold.
Reaction of Metals with Dilute Acids
Metal salt and hydrogen gas are formed when a metal reacts with dilute acid.
Metal + Dilute Acid → Metal Salt + Hydrogen
However, all metals do not react with dilute acids. The intensity of the reaction of metal with dilute acids depends on its chemical reactivity. Some metals react explosively or extremely rapidly, some metals react rapidly, some react on heating whereas others do not react at all.
Some examples are given below:
- Reaction of Sodium with dilute hydrochloric acid: Sodium metal reacts violently with dilute hydrochloric acid to form sodium chloride and hydrogen gas.
2Na + 2HCl → 2NaCl + H2
(Sodium) (Hydrochloric acid) (Sodium chloride) (Hydrogen)
- Reaction of Magnesium with dilute hydrochloric acid: Magnesium metal reacts quite rapidly with dilute hydrochloric acid to form magnesium chloride and hydrogen gas.
Mg + 2HCl → MgCl2 + H2
(Magnesium) (Hydrochloric acid) (Magnesium chloride) (Hydrogen)
The reaction of magnesium with dilute hydrochloric acid is less vigorous than that of sodium.
- Reaction of Aluminium with dilute hydrochloric acid: Due to the presence of a strong layer of aluminium oxide on its surface, the aluminium metal reacts slowly with dilute hydrochloric acid at first. But when the oxide layer gets dissolved in acid, then the aluminium layer is exposed which reacts rapidly with dilute hydrochloric acid. Aluminium chloride and hydrogen gas are formed when aluminium metal reacts rapidly with dilute hydrochloric acid.
2Al + 6HCl → 2AlCl3 + 3H2
(Aluminium) (Hydrochloric acid) (Aluminium chloride) (Hydrogen)
Metals like zinc and iron react very slowly with dilute hydrochloric acid. Copper does not react with dilute sulphuric acid (or dilute hydrochloric acid) at all.
- Reaction of Zinc with dilute sulphuric acid: Zinc sulphate and hydrogen gas are formed when zinc metal reacts with dilute sulphuric acid. In the laboratory, this method is used to produce hydrogen gas.
Zn + H2SO4 → ZnSO4 + H2
(Zinc) (Sulphuric acid) (Zinc sulphate) (Hydrogen)
When metals react with dilute nitric acid, then hydrogen gas is not evolved. However, very dilute nitric acid reacts with magnesium metal to evolve hydrogen. This is because the very dilute nitric acid is a weak oxidizing agent which is not able to oxidize hydrogen to water.
- Reaction of Magnesium with very dilute nitric acid: Magnesium nitrate and hydrogen gas are formed when magnesium metal reacts with very dilute nitric acid.
Mg + 2HNO3 → Mg(NO3)2 + H2
(Magnesium) (Nitric acid) (Magnesium nitrate) (Hydrogen)
Reaction of Metals with solutions of other Metal Salts.
A displacement reaction occurs when metals react with a solution of another metal salt. The more reactive metal displaces the less reactive metal from its salt in this reaction.
Metal A + Salt of metal B → Salt of Metal A + Metal B
Some examples are given below:
- Reaction of Zinc with Copper Sulphate Solution: When a strip of zinc metal is put in a copper sulphate solution, then the blue colour of copper sulphate fades gradually due to the formation of colourless zinc sulphate solution, and on the zinc strip, a red-brown copper metal is deposited.
Zn + CuSO4 → ZnSO4 + Cu
(Zinc) (Copper sulphate) (Zinc sulphate) (Copper)
- Reaction of Iron with Copper Sulphate Solution: Iron displaces copper from copper sulphate solution.
Fe + CuSO4 → FeSO4 + Cu
(Iron) (Copper sulphate) (Iron (II) sulphate) (Copper)
In the above examples, zinc and iron are more reactive than copper. As a result, copper is displaced from its salt solution.
- Reaction of Copper with Silver Nitrate solution: When a strip of copper metal is put in silver nitrate solution, then the solution gradually becomes blue and a shining greyish-white deposit of silver metal is formed on the copper strip.
Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
(Copper) (Silver Nitrate) (Copper nitrate) (Silver)
Copper is more reactive than silver in this reaction, therefore it displaces silver from the silver nitrate solution.
Silver and gold metal do not react with copper sulphate solution because silver and gold are less reactive than copper and are not able to displace copper from its salt solution.
Reaction of Metals with Chlorine.
Metals react with chlorine to form metal chlorides. In the formation of metal chlorides, the metal atom loses electrons and become positively charged ions, whereas chlorine atoms gain electrons and become negatively charged ions.
Some examples are given below:
- Reaction of Sodium with chlorine: Sodium metal readily reacts with chlorine to form sodium chloride.
2Na + Cl2 → 2NaCl
(Sodium) (Chlorine) (Sodium chloride)
- Reaction of Magnesium with chlorine: Magnesium metal on heating readily reacts with chlorine to form magnesium chloride.
Mg + Cl2 → MgCl2
(Magnesium) (Chlorine) (Magnesium chloride)
- Reaction of Zinc with chlorine: Zinc metal directly combines with chlorine to form zinc chloride.
Zn + Cl2 → ZnCl2
(Zinc) (Chlorine) (Zinc chloride)
Reaction of Metals with Hydrogen.
Metals generally do not react with hydrogen because metals form compounds by losing electrons and hydrogen also form compounds by losing electrons (or by sharing electrons). So most of the metals do not form compounds with hydrogen. Metal hydrides are formed when a few reactive metals, such as sodium, potassium, magnesium, and calcium, react with hydrogen.
Some examples are given below:
- Reaction of Sodium with hydrogen: Sodium hydride is formed when hydrogen gas is passed over heated sodium.
2Na + H2 → 2NaH
(Sodium) (Hydrogen) (Sodium Hydride)
- Reaction of Calcium with hydrogen: Calcium hydride is formed when hydrogen gas is passed over heated calcium.
Ca + H2 → CaH2
(Calcium) (Hydrogen) (Calcium Hydride)
Sample Questions
Question 1: What happens whenever a zinc sulphate rod is dipped in a copper sulphate solution?
Answer:
When a rod of zinc is dipped in a copper sulphate solution, then the blue color of copper sulphate fades gradually due to the formation of colorless zinc sulphate solution, and red brown copper metal is deposited on the zinc rod.
Question 2: Why do some metals like sodium and potassium not occur in nature as free elements?
Answer:
Metals like sodium and potassium are very reactive and hence they react with atmospheric oxygen to form compounds like oxides, so they do not occur in free states.
Question 3: Why don’t most metals form compounds with hydrogen? Name a metal that forms compounds with hydrogen and give a reaction.
Answer:
Metals form compounds by losing electrons and hydrogen also form compounds by losing electrons (or by sharing electrons). So most of the metals do not form compounds with hydrogen. Sodium metal form compounds with hydrogen.
Sodium hydride is formed when hydrogen gas is passed over heated sodium.
2Na + H2 → 2NaH
Question 4: Which oxide of iron is formed on the reaction of iron with steam?
Answer:
Iron forms iron oxide and hydrogen gas when it reacts with steam.
3Fe + 4H2O → Fe3O4 + 4H2
Question 5: What happens when a copper plate is immersed in dilute sulphuric acid?
Answer:
Since copper does not react with dilute sulphuric acid, so when dilute sulfuric acid is poured on a copper plate, no reaction occurs.
Question 6: In a silver nitrate solution, a copper plate was dipped. Silver from the solution was deposited on the copper plate after some time. Based on this observation, find out which is more reactive – copper or silver?
Answer:
In a salt solution, a more reactive metal displaces a less reactive metal. Here copper metal is displacing silver from silver nitrate solution, therefore, copper metal is more reactive than silver metal.