Goyal Brothers Class-10 Chemical Bonding Ionic and Covalent Compound Ch-2

Goyal Brothers Class-10 Chemical Bonding Ionic and Covalent Compound ICSE Chemistry Solutions Ch-2. Step by Step Solutions of Exercise and Objective Type Questions of Goyal Brothers Prakashan Chapter-2 Chemical Bonding Ionic and Covalent for ICSE Class 10 Chemistry.  Visit official Website CISCE  for detail information about ICSE Board Class-10 Chemistry .

Goyal Brothers Class-10 Chemical Bonding Ionic and Covalent Compound ICSE Chemistry Solutions Ch-2


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Objective Type Questions (update soon)


Exercise Goyal Brothers Class-10 Chemical Bonding Ionic and Covalent Compound ICSE Chemistry Solutions Ch-2

Question-1

 (a) Why do most of the elements form ions?
(b) What kind of elements form cations? Support your answer by two examples
(c) What kind of elements form anions? Support your answer by two example

Answer

(a) Most metals become cations when they make Ionic  compounds. Some  atoms have nearly eight electrons in their valence shell and can gain additional valence electrons until they have an octet. When these atoms gain electrons, they acquire a negative charge because they now possess more electrons than protons

(b) Cations can be formed from metal elements, as well as nonmetal elements. If a metal element forms an ion, it always forms a cation. Some metals always form the same type of cation. For example, sodium always forms a +1 cation and magnesium always forms a +2 cation

(c) They are formed when non-metal gains the electrons. They gain one or more than one electron and do not lose any protons. Therefore, they possess a net negative charge. Some examples of anions are Iodide (I), chlorine (Cl), hydroxide (OH)

Question-2

Explain the formation of a molecule of oxygen by sharing pair/pairs of electrons

Answer

A simple view of double covalent bonds

A double covalent bond is where two pairs of electrons are shared between the atoms rather than just one pair.

Oxygen, O2

Two oxygen atoms can both achieve stable structures by sharing two pairs of electrons as in the diagram.

Question-3

.State four periodic properties which are responsible for the formation of ionic and covalent compound

Answer

four periodic properties which are responsible for the formation of Ionic Compound

  1. large deference in ionisation potential
  2. large deference in electron affinity
  3. large deference in electronegativity
  4. large deference in ionic radius

four periodic properties which are responsible for the formation of covalent compound

  1. Less deference in ionisation potential
  2. Less deference in electron affinity
  3. Less deference in electronegativity
  4. Less deference in ionic radius

Question-4

Fill in the blank spaces with appropriate word/words.
(a) An ionic compound is formed when the ..……..between the values of electronegativities of the two combining atom is very large

(b)   …………………………

(C)  ……………………  …………

(d) ……………….. in the lionization potential of the two atoms leads to the formation of ionic bond

Answer

(a) An ionic compound is formed when the ..atoms…between the values of electronegativities of the two combining atom is very large

(b)   ……….. covalent………..

 (C)  …………higher deference in  …………

(d) More difference in the lionisation potential of the two atoms leads to the formation of ionic bond

Question-5

What do you understand by the term ionic bond? State at least three conditions for its formation

Answer

Electrovalent or ionic bond: The chemical bond formed between two atoms by transfer of one or more electrons from the atom.

Electrovalent or ionic compound: The chemical compound formed as a result of transfer of one or more electrons from atom.

Question-6
Explain the following
(a) Why are ionic compounds crystalline solids
(b) Why do ionic compounds have high melting and boiling points?
(c) Why are ionic compounds soluble in water?
(d) Why are ionic compounds good conductors of electricity in the fused state or in aqueous solution

Answer

(a) Ionic compounds form when metals transfer valence electrons to nonmetals. Ionic compounds exist as crystals rather than molecules. due to strong electrostatic force of attraction makes lattice arrangement.
(b) Ionic compounds are held together by electrostatic forces between the oppositely charged ions . As the ionic lattice contains such a large number of ions, a lot of energy is needed to overcome this ionic bonding so ionic compounds have high melting and boiling points
(c) Most ionic compounds are soluble in water. Polar water molecules have a strong attraction for charged ions and the charged ions become solvated as they dissociate into water and ionic compounds are soluble in water.
(d) Ionic compounds conduct electricity when molten (liquid) or in aqueous solution (dissolved in water), because their ions are free to move from place to place. Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move.

Question-7

What do you understand by the term covalent bond? Show the formation of covalent bonds in (a) Cl (B) Oxygen (C) nitrogen, by dot diagrams.

Answer

Covalent bond, in chemistry, the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the electrostatic attraction of their nuclei for the same electrons

To get  dot diagrams. of (a) Chlorine (B) Oxygen (C) nitrogen refer to page number-26 of your current text book

Question-8

Define

(a) Non Polar covalent compound

(b) polar covalent compound.

Support your answer by giving at least one example

Answer

(a) A non-polar covalent bond is a type of chemical bond that is formed when electrons are shared equally between two atoms. … It further means that there is no separation of charges between the two atoms or both the atoms have similar electronegativity

Ex- Chlorine, Oxygen and Nitrogen Molecule formation

(b) polar covalent compound.  Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms due to difference in their electro-negativities. These compounds are called polar covalent compounds. An example is , where both have different electro-negativities.

concept

Question-9

Give three differences between polar covalent compound HCI, and non-polar covalent compound Methane

Answer

Non-polar covalent compound(Methane,CH4)

1. Covalent compounds are said to be non-polar when shared pair of electrons are equally distributed between the two atoms.

2. No charge separation takes place.The covalent molecule is symmetrical and electrically neutral.

Polar covalent compound (HCl)

1. Covalent compounds are said to be polar when shared pair of electrons are unequally distributed between the two atoms.

2. Charge separation takes place.The atom which attracts electrons more strongly develops a slight negative charge while the other develops a slight positive charge.

Question-10
Explain the following:
(a) Why are covalent compounds generally gases or liquids or soft solid
(b) Why do covalent compounds have low melting points and boiling Point
(c) Why are non polar covalent compounds insoluble in water
(d) Why are polar covalent compounds soluble in water?

(e) Why are non-polar covalent compounds bad conductors of electricity
(f) Why are polar covalent compounds good conductors of electricity

Answer

(a) Covalent compounds exists as gasesliquids or soft solids because they have weak forces of attraction between their molecules.

(b)  The molecules in covalent compounds are held by weak van der Waal’s forces, hence they have low melting points and boiling points as a compared to ionic compounds.
(c)  Nonpolar compounds do not dissolve in water. The attractive forces that operate between the particles in a nonpolar compound are weak dispersion forces. However, the nonpolar molecules are more attracted to themselves than they are to the polar water molecules.
(d) Substances that dissolve into a solvent are called solutes, and the resulting mixture is a solution. Water is an excellent solvent because its polar water molecules form hydrogen bonds with ions and polar molecules, allowing ionic and polar covalent compounds to disperse easily in water

(e) Why are non-polar covalent compounds bad conductors of electricity   because covalent bonds are formed by sharing of electrons..they don’t have a free electron that is required for electricity transfer(electricity is the flow of  free electrons!) thus they re bad conductors
(f) polar covalent compounds are good conductor of electricity because the shared pair of electron is not equally distributed therefore,both the atoms has got some slight charge. those charge is due to free electron.  The element which has free electron conducts electricity

Question-11. 

what is lone pair effect? In which kind of compounds does this effect occurs? By drawing dot diagrams, show lone pairs
in (a) ammonia (6) water

Answer

The presence of a lone pair decreases the bond angle between the bonding pair of electrons, due to their high electric charge which causes great repulsion between the electrons. so it is called lone pair effect

 dot diagrams, showing lone pairs in (a) ammonia

dot diagrams, showing lone pairs in (b) water

New Simplified Chemistry Class 10 ICSE Solutions Chapter 2 Chemical Bonding 1

Question-12

By drawing dot diagrams, show lone pair effect leading to the formation of (a) ammonium ions (b) hydronium ions from the molecules of ammonia and water respectively.

Answer

 (a) ammonium ions from ammonia

chemical-bonding-icse-solutions-class-10-chemistry-17

(b) hydronium ions from water

New Simplified Chemistry Class 10 ICSE Solutions Chapter 2 Chemical Bonding 1

Question-13,

 Taking sodium chloride as an example of an ionic compound and carbon tetrachloride as an example of a molecular Compound, give two differences between ionic compounds and molecular compounds.

Answer

Electrical conductivity: An ionic compounds do not conduct electricity in solid state because there is no free ions or electrons but when dissolved in water they conduct electricity very well as ions are able to carry charges whereas a molecular compound does not conduct electricity either in its pure form or when dissolved in water due to lack of free ions, they do not carry electric charge very well, and thus, act as poor conductors of electricity

Melting and boiling points: Ionic compounds have high melting and boiling points because high temperatures are required to overcome the attraction between the positive and negative ions in ionic compounds and therefore a lot of energy is required to melt ionic compounds while molecular compound has low melting points due to large molecules which are solid. On melting and boiling, low temperatures are required to break intermolecular forces of attractions in which lower energy is used.

Question-14
1, the electron arrangement of atoms of three elements A, B and C is: A (2, 8, 1); B (2, 8, 6); C (2, 8, 18,7).
(a) write down the formula of the molecule of B and its electron dot diagram. Mention the type of bonding
(b) Write down the formula of the compound formed between A and C and type of bonding.

Answer-

(a) The element B2 of non polar covalent bond

(b) the formula between A and C is AC . The type of bond is Ionic.


 Objective Type Questions

 I. Multiple Choice Questions
Choose the correct answer from the options given below :

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