Reactions of Metals with Non-metals: Definition, Ionic Compounds, Properties

Reactions of Metals with Non-metals: How do metals and non-metals combine? When a metal and a non-metal react with each other, the metal atom donates its outer electrons, and the non-metal atom gains these electrons to form an ionic bond between them. Why does a metal atom donate its outer electron and a non-metal atom gains electrons? How is an ionic bond formed? Let us answer these interesting questions in this article.

Ionic Bond or Electrovalent Bond

The chemical bond formed by the transfer of electrons from one atom to another is an ionic bond or electrovalent bond. The transfer of electrons takes place so that the ions formed will have the stable electron arrangement of inert gas. This bond is called an ionic bond because it is a chemical bond between oppositely charged ions.

An ionic bond is formed when one of the atoms can donate electrons to achieve the nearest noble gas electron configuration. The other atom needs electrons to achieve the inert gas electron configuration.

Generally, metal atoms have \(1,2\) or \(3\) electrons in their outermost shell. They can donate it to form stable positive ions. Similarly, non-metals have usually \(5,6\) or \(7\) electrons in their outermost shell. They gain electrons to form stable negative ions. Therefore, when a metal reacts with a non-metal, the transfer of electrons takes place from the metal atoms to the non-metal atoms. As a result, an ionic bond is formed.

When forming an ionic bond, the metal atoms donate electrons to form a positive ion (cation) and the non-metal atom gains electron to form a negative ion (anion). The positive and negatively charged ions attract each other. The strong force of attraction developed between the oppositely charged ions is known as an ionic (electrovalent) bond. The compounds containing such ionic bonds are called ionic (electrovalent) compounds.

Formation of Ionic Compounds

We are now familiar with that, an ionic compound is generally formed between a metal and a non-metal. Examples of such compounds include sodium chloride, magnesium chloride, lithium fluoride, calcium chloride, etc. Let us discuss the formation of different ionic compounds in detail.

1. Formation of Sodium Chloride

Sodium is a metal. Chlorine is a non-metal. The atomic number of sodium is \(11.\) Therefore, it has one electron in its outermost shell. Similarly, the atomic number of chlorine is \(17.\) It has seven electrons in its outermost shell.

To form a stable positive ion, a sodium atom donates its one outer electron to form a sodium \(\left({{\text{N}}{{\text{a}}^ + }} \right)\) ion. That is,

And similarly, to form a stable negative ion, the chlorine atom gains one electron to form a chloride \(\left( {{\rm{C}}{{\rm{l}}^ – }} \right)\) ion. That is,

When sodium reacts with chlorine, it transfers its one outermost shell electron to the chlorine atom. By losing one electron, the sodium atom forms a sodium \(\left({{\text{N}}{{\text{a}}^ + }} \right)\) ion, and by gaining one electron, the chlorine forms a chloride \(\left( {{\rm{C}}{{\rm{l}}^ – }} \right)\) ion. Which can be represented as:

Here, the sodium ion has a positive charge, and the chloride ion has a negative charge. Due to the opposite charges, the sodium and the chloride ions are held together by the strong electrostatic force of attraction to form sodium chloride.

2. Formation of Magnesium Chloride

Magnesium is a metal, and chlorine is a non-metal. The atomic number of magnesium is \(12.\) It has two electrons in its outermost shell. Similarly, the atomic number of chlorine is \(17.\) It has seven electrons in its outermost shell.

In order to form a stable positive ion, the magnesium atom donates its two outermost shell electrons to form a magnesium \(\left({{\text{M}}{{\text{g}}^{2 + }}} \right)\) ion. That is,

Similarly, to form a stable negative ion, the chlorine atom gains one electron to form a chloride \(\left( {{\rm{C}}{{\rm{l}}^ – }} \right)\) ion. Since magnesium donates two electrons, two chlorine atoms take these two electrons to form a \(2{\text{C}}{{\text{l}}^ – }\) ion. That is,

During the formation of magnesium chloride, the magnesium atom transfers its two electrons to two chlorine atoms. By losing two electrons, the magnesium atom forms a magnesium \(\left({{\text{M}}{{\text{g}}^{2 + }}} \right)\) ion, and by gaining two electrons, the two chlorine atoms form two chloride \(\left( {2{\rm{C}}{{\rm{l}}^ – }} \right)\) ions. That is,

Here, the positively charged magnesium ion and the negatively charged chloride ion are held together by the strong electrostatic force of attraction to form magnesium chloride.

3. Formation of Lithium Fluoride

Lithium is metal, and fluorine is non-metal. The atomic number of lithium is three. Therefore, it has one outer shell electron. The atomic number of fluorine is \(9.\) Hence, it has seven electrons in its outermost shell.

Now to form a stable positive ion, lithium loses its one outer electron and forms lithium \(\left({{\text{L}}{{\text{i}}^ + }} \right)\) ion. That is,

Now to form a stable negative ion, the fluorine atom gains one electron to form a fluoride \(\left( {{{\rm{F}}^ – }} \right)\) ion. That is,

During the formation of lithium fluoride, the lithium atom donates its one outer electron to a fluorine atom. This can be represented as,

The lithium-ion and the fluoride ion are held by a strong electrostatic force of attraction which is known as the ionic bond.

4. Formation of Calcium Chloride

Calcium is a metal, and chlorine is a non-metal. The atomic number of calcium is \(20.\) It has two electrons in its outermost shell. The atomic number of chlorine is \(17.\) Therefore, it has seven electrons in its outermost shell.

In order to form a stable positive ion, the calcium atom donates its two electrons to form a calcium \(\left({{\text{C}}{{\text{a}}^{2 + }}} \right)\) ion. That is,

Now to form a stable negative ion, a chlorine atom gains one electron and forms a chloride \(\left( {{\rm{C}}{{\rm{l}}^ – }} \right)\) ion. Since calcium donates two electrons, two chlorine atoms take these two electrons to form a \(2{\text{C}}{{\text{l}}^ – }\) ion. That is,

During the formation of calcium chloride, calcium atoms donate their two outermost shell electrons to two chlorine atoms. It can be shown as,

The two oppositely charged calcium and chloride ions are held together by strong electrostatic attractive forces. Thus an ionic bond exists between calcium and chloride ions.

Characteristics of Ionic Compounds

Let us discuss some properties of ionic compounds.

Physical State

Ionic compounds are generally crystalline solids and somewhat hard. The hardness is due to the strong force of attraction between the positive and negative ions.

Ionic compounds are generally brittle and break into pieces when external pressure is applied.

Melting and Boiling Points

Ionic compounds generally have very high melting and boiling points. This is because of the strong inter-ionic force of attraction that holds the ions tightly in their crystal lattice. Therefore, to remove the ions from their positions, a large amount of energy is needed to overcome the forces of attraction between the oppositely charged ions.

Solubility

Ionic compounds are readily soluble in polar solvents like water, liquid ammonia, etc. they are insoluble in non-polar solvents like kerosene, petrol, benzene, carbon tetrachloride, etc.

Study Occurrence of p-block Elements

Conduction of Electricity

 In solid-state, ionic compounds will not conduct electricity. This is because, in the solid-state, the ions are held tightly together by a strong electrostatic force. As a result, the ions in them occupies a fixed position in the crystal lattice. Therefore, the ions cannot move when the electric current is applied.

However, the ionic compounds conduct electricity in molten or in aqueous solutions. That is, when an ionic compound is dissolved in water, forces of attraction between them are weakened and is broken by the high dielectric constant of water, and as a result, the ions constituting the ionic compound are separated from each other and become to move about in the liquid medium by the influence of applied electric current.

Similarly, when an ionic compound is heated, the kinetic energy of the ions increases, and they break and movely. Therefore, in the molten state, the forces of attraction are weakened, and as a result, ionic solids are good conductors of electricity in the molten state.

Summary

We have now understood how metals and non-metals combine together. They combine together to form ionic or electrovalent compounds. Ionic compounds are generally crystalline solids. They have high melting and boiling points, and they conduct electricity in an aqueous and in molten state. The formation of different ionic compounds and the different properties of such compounds are explained in this article.

FAQs on Reactions of Metals with Non-metals

Q.1. How do metals and non-metals react?
Ans: Metals react with non-metals by transferring electrons between them. The bond formed by such transfer is called an ionic bond. Such types of compounds formed are called ionic compounds.

Q.2. What happens when non-metals bond with metals?
Ans: When a metal reacts with a non-metal, a metal atom donates its outermost shell electrons, and the non-metal atoms gain these electrons to form an ionic bond between them.

Q.3. Can two non-metals react?
Ans: Yes, two non-metals can react with each other to form covalent compounds.

Q.4. What is the bonding between a metal and a non-metal called?
Ans: The bond formed between a metal and a non-metal is known as an electrovalent bond or ionic bond.

Q.5. Can two metals form a covalent bond?
Ans: No, Metals cannot form a covalent bond. However, two non-metals combine with each other to form a covalent bond.

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