Students of ICSE Class 10 should refer to Chemical Bonding ICSE Class 10 Chemistry board year questions and solutions. below which have come in past board exams. You should always go through questions that have come in previous years. This will help you to understand the pattern of questions in ICSE Class 10 Chemistry and prepare accordingly. This will help you to get better marks in ICSE Class 10 Board Exams
ICSE Class 10 Chemistry Chemical Bonding Board Exam Questions
Students should learn the important questions and answers given below for Chapter Chemical Bonding in Chemistry for ICSE Class 10. These board questions are expected to come in the upcoming exams. Students of ICSE Class 10th should go through the below board exams questions and answers which will help them to get more marks in exams.
Board Exam Questions Chemical Bonding ICSE Class 10 Chemistry
Fill in the blanks in the following statements, with suitable words :
Question: Ionic compounds consist of …………………………………. charged ions.
Answer:
oppositely
Question: Ionic compounds have ………………….. melting points due to ………………. ionic bonds.
Answer:
high, strong
Question: The physical state of ionic compounds is ………………..….. .
Answer:
solid state
Question: Ionic compound conduct electricity in their …………………. .
Answer:
fused state as well as in their aqueous solution
Question: The nature of bond in compounds of alkali and alkaline earth metals is ………..………. .
Answer:
ionic bond
Question: ………………… compounds have low boiling points because of …….……….. intermolecular forces.
Answer:
covalent, weak
Question: In covalent compounds, the bond is formed due to the……………………of electrons.
Answer:
sharing
Question: Melting and boiling points of covalent compounds are generally………………….……
Answer:
low
Question: Covalent bond is rigid and directional, it is responsible for ……………………. .
Answer:
definite shape of the molecule
Question: Most covalent compounds have density …………………. than that of water.
Answer:
less
Question: The electronegativities of atoms giving covalent molecules are generally …………..……… .
Answer:
high
Question: Atoms of the same element combine to form molecules by means of ……………………. bonds.
Answer:
covalent
Question: A solution of a ………………..…. electrolyte will contain both ions and molecules of the solute.
Answer:
strong
Question: In the sodium chloride crystal, each Na+ ion is surrounded by …………………… Cl– ions and each
Cl– ion by …………………….. Na+ ions.
Answer:
six, six
Question: In sodium chloride, the Na+ ion has the ……………………. configuration and the Cl– ion has the …………………… configuration.
Answer:
neon, argon
Question: A compound conducted electricity in the fused state. The compound is made-up of………………… .
Answer:
ions
Question: The duplet or octet structure of valence shell makes …………………. of an element chemically ………………….
Answer:
atom, inactive
Question: The atomic number of oxygen is 8. The total number of electrons in the O2– ion is ……………………..…… .
Answer:
10
Question: The atomic number of oxygen is 8. The number of protons in the O2– ion is ……………..….. .
Answer:
8
Question: Two nitrogen atoms join together by sharing …………………….. pairs of electrons.
Answer:
three
Question: In NH4+ all the four bonds are……………..…… .
Answer:
identical
Question: The water molecules easily break the ……………….. bonds between the oppositly charged ions. The ions drift in water in all possible directions and hence electrovalent compounds ………………………………. in water.
Answer:
ionic, dissolve
Question: A molecule of……………………………contains a triple bond.
Answer:
nitrogen
Question: ………………… are identical to a normal covalent compound.
Answer:
co-ordinate bond
Question: Metals are good …………………………because they are electron…………………………….
Answer:
reducing agents, donors
Question: Electrovalent compounds have……………………………..…melting points.
Answer:
high
Multiple Choice Questions
Questions. Molecular reactions which are generally slow reactions are shown by :
(a) Covalent compounds
(b) Ionic compounds
(c) Co-ordinate compounds
(d) Both ionic and covalent compounds
Answer
D
Questions. The number of electrons lost or gained by an atom refers to :
(a) Electrovalency
(b) Covalency
(c) Donation
(d) Acceptance
Answer
A
Questions. The capacity of an atom to attract the shared pair of electrons towards itself is called :
(a) Electronegativity
(b) Electron affinity
(c) Sharing of electrons
(d) Electron donation
Answer
A
Questions. Which of the following doesn’t represent oxidation ?
(a) Loss of electrons
(b) Addition of oxygen
(c) Increase in oxidation number
(d) Addition of hydrogen
Answer
D
Questions. Sodium and sodium ions :
(a) Are chemically same
(b) Have same number of electrons
(c) Have same number of protons
(d) None of the above
Answer
C
Questions. A compound which contains all the three types of bonds i.e., ionic, covalent and coordinate is :
(a) Sodium chloride
(b) Ammonia
(c) Calcium chloride
(d) Ammonium chloride
Answer
D
Questions. The most ionic compound of periodic table is :
(a) Sodium chloride
(b) Potassium chloride
(c) Magnesium chloride
(d) Caesium chloride
Answer
D
Questions. The molecule containing a triple covalent bond is :
(a) Ammonia
(b) Methane
(c) Water
(d) Nitrogen
Answer
D
Questions. A compound having one lone pair of electrons :
(a) Water
(b) Methane
(c) Ammonia
(d) Hydrogen sulphide
Answer
C
Questions. A compound X consists of only molecules. Hence X will have :
(a) A crystalline hard structure
(b) A low melting point and low boiling point
(c) An ionic bond
(d) A strong force of attraction between its molecules
Answer
B
Questions. Bonding in this molecule can be understood to involve coordinate bonding :
(a) Carbontetrachloride
(b) Hydrogen
(c) Hydrogen chloride
(d) Ammonium chloride
Answer
D
Questions. Which of the following is a common characteristic of a covalent compound ?
(a) High melting point
(b) Consists of molecules
(c) Always soluble in water
(d) Conducts electricity when it is in the molten state
Answer
B
Give One Word/Chemical Term
Question. A bond formed by the transfer of electrons.
Answer
Electrovalent bond
Question. A bond formed by the sharing of electrons.
Answer
Covalent bond
Question. A bond formed by a shared pair of electrons with both electrons coming from the same atom.
Answer
Coordinate bond
Question. Bond present in metallic chloride and between two chlorine atoms.
Answer
Electrovalent, covalent
Question. Electrons lost or gained by an atom in compound formation.
Answer
Electrovalency
Question. Ions formed by the loss and gain of electrons respectively.
Answer
Cation and anion respectively
Question. The process in which an atom lose electrons.
Answer
Oxidation
Question. The process in which an atom gain electrons.
Answer
Reduction
Question. An inert gas which contain triple bond.
Answer
Nitrogen
Question. A molecule with little affinity.
Answer
Methane
Question. Two molecules, which are polar.
Answer
Hydrogen chloride, Ammonia
Question. A polar covalent molecule.
Answer
Hydrogen chloride (HCl)
Question. A non-polar covalent compound.
Answer
Carbon dioxide (CO2)
Question. A covalent molecule which on dissolving form ions.
Answer
HCl
Question. A molecule with one lone pair and three bond pairs.
Answer
Ammonia (NH3)
Question. A molecule with two lone pairs and two bond pairs.
Answer
Water (H2O)
Define/Explain the Following
1. Chemical bond
An attractive force which hold atoms, ions or molecules together, is known as a chemical bond or linkage.
2. Electrovalent bond
A chemical bond formed by transfer of one or more electrons between two atoms, is known as electrovalent or polar ionic bond.
3. Electrovalency
The number of electrons lost or gained by an atom, is called the electrovalency of that element.
4. Covalent bond
The bond formed by equal contribution and mutual sharing of electrons between two atoms so that both the atoms acquire the stable nearest noble gas configuration i.e., get their octet complete is called covalent bond.
5. Polar covalent bond
When a covalent bond is formed between two atoms having different electronegativities, the shared pair of electrons is attracted more towards the atom having higher electronegativity. This atom acquires a partial negative charge other atom acquires a partial positive charge.
6. Non-polar covalent bond
When a covalent bond is formed between two identical atoms of the same element, the shared pair of electrons is attracted equally by both the bonded atoms. Such a covalent bond is called non-polar covalent bond. e.g., Cl–Cl, H–H etc.
7. Co-ordinate bond.
A co-ordinate bond is a special type of covalent bond which is formed by one side sharing of lone pair of electron between the two atoms.
8. Lone pair
Lone pair is defined as the pair of electrons which are not shared by any of the reacting atoms. Lone pair of electrons is actually responsible for its basic nature. Example of lone pairs are NH3, H2O.
9. Hydronium ion
It is a hydrogen ion in association with a molecule of water. In a water molecule, the oxygen atom has two pairs of unshared electrons. The hydrogen ion does not have any electron in the valence shell. Hence, it shares a pair of electrons from the oxygen atom by means of co-ordinate valency to from an H3O+ ion.
10. Electropositive elements
Elements producing cations are known as electropositive elements, e.g. Na+, K+, etc.
11. Electronegative elements
Those elements which produce anions are called as electronegative elements, e.g., Cl–, N3–etc.
Reasoning Based Questions
Q. 1. Why atoms combine with one another ?
Answer
The cause of chemical combination between atoms of the various elements is their tendency to acquire nearest stable noble gas configuration of octet of electrons and duplet of electrons in case of hydrogen atoms in their outermost shells.
Q. 2. Why do certain elements form ions ?
Answer
Every particle (molecule, atom or ion) has the tendency to attain the state of lowest energy. As atoms of all elements except the noble gases, have one to seven electrons in their outermost shell, therefore, they are not in the state of minimum energy. They are reactive. In order to attain a minimum state of energy, i.e., to acquire a duplet or octet structure in their valence shell, they either donate or accept electrons. In this process, they become charged particles or ions.
Q. 3. Why all atoms other then noble gas atoms are reactive ?
Answer
All atoms other then noble gas atoms are reactive because they are short of octet in their outermost shell. They tend to attain eight electrons in their outermost shell to acquire nearest inert gas electronic configuration.
Q. 4. Why a molecule of hydrogen is more stable than the uncombined atoms ?
Answer
When a molecule of hydrogen is formed from the atoms, energy is released (104 kcal/mol). The molecules possessing lower energy are more stable, than the atoms. Hence molecule of hydrogen is more stable than uncombined atoms.
Q. 5. Why is hydrogen ion called proton ?
Answer
An atom of hydrogen has one proton in its nucleus and one electron in its valence shell. It donates its valence electron, the residual ion consists of a single proton. It is on account of this fact, that hydrogen ion is called proton.
Q. 6. A cation is smaller than the atom from which it is formed. Why ?
Answer
In the formation of a cation, the atom loses the electrons of its outer shell. Thus, the cation has one electron shell less than the atom, from which it is formed. So, it is smaller than the atom.
Q. 7. An anion carries negative charge. Why ?
Answer
When an atom forms an anion, it gets one or more electrons (from another atom) in its outer shell. As the number of electrons in the outer shell is increased, the repulsion between them increases. This makes the shell expand outward. Further, since the number of protons remains the same as in the neutral atom, the nucleus attracts the increased number of electrons less strongly. For these reasons the anion is bigger than the parent atom.
Q. 8. Why electrovalent compounds form hard crystals ?
Answer
The crystals of electrovalent compounds are made up of crystal lattice containing oppositely charged ions. Each cation is surrounded by a definite number of anions and vice-versa. Their is a great electrostatic force of attraction among these oppositely charged ions and as a result, ionic compounds form hard crystals.
Q. 9. Why electrovalent compounds have high melting, boiling points and low volatility ?
Answer
There is a strong force of attraction among the oppositely charged ions in the crystals of electrovalent compounds. Therefore, a large amount of energy is required to separate them. Due to these strong forces of attraction, ionic compounds have high melting and boiling points and low volatility.
Q. 10. Why electrovalent compounds in crystalline state do not conduct electricity ?
Answer
Electrovalent compounds in crystalline state do not conduct electricity because the oppositely charged ions in them are held together by a strong electrostatic force of attraction. These ions occupy fixed position in the crystals and do not move when an electric field is applied.
Short Questions
Q. 1. The combination of atoms to form molecules is based on octet rule. Give two limiations of this rule.
Answer
(i) It cannot explain the formation of molecules like BeF2, BF3 in which the central atom has less than 8 electrons in its valence shell.
(ii) It cannot explain the formation of molecules such as PF5, SF6 etc., in which central atom has more than eight electrons in its valence shell.
Q. 2. Write the general characteristics of electrovalent compounds.
Answer
The general characteristics of electrovalent compounds are :
(i) Electrovalent compounds are mostly crystalline in nature.
(ii) Electrovalent compounds form hard crystals. These crystals are usually brittle.
(iii) Electrovalent compounds have high density with high melting and boiling points.
(iv) Electrovalent compounds are soluble in polar solvents.
(v) Electrovalent compounds exhibit isomorphism.
(vi) They react very fast.
Q. 3. On what factors the formation of an electrovalent compound depends ?
Answer
The formation of an ionic or electrovalent compound depends on the following factors :
(i) Low ionisation energy : Lesser is the ionisation energy of an atom, greater will be its tendency to form cation by losing the valence electron. Metals with lower ionisation energy values have a greater tendency to form ionic bonds.
(ii) High electron affinity : Higher the value of electron affinity, greater will be the tendency of the atom to gain electron and form an anion. Elements with high electron affinity values form ionic compounds.
(iii) High lattice energy : The higher is the value of lattice energy, greater will be the electrostatic force of attraction between the oppositely charged ions and hence ionic compounds are formed with greater ease by release of energy.
Q. 4. What are the salient features of electrovalency ?
Answer
Some salient features of electrovalency are as follows :
(i) An electrovalent bond is formed by loss or gain or transfer of electrons.
(ii) Ions are formed during the formation of an electrovalent bond.
(a) Positive ions ⎯→ Cations (Na+, K+, Ca2+, etc.)
(b) Negative ions ⎯→ Anions (Cl–, O2–, N3–, etc.)
(iii) An electrostatic force of attraction exist between the oppositely charged ions.
(iv) There is one fixed direction in space among the ions.
Q. 5. Write the important characteristics of covalent compounds.
Answer
The important characteristics of covalent compounds are as follows :
(i) Usually covalent compounds exist in gaseous, liquid or amorphous state.
(ii) Covalent compounds have low melting or boiling points.
(iii) Except for graphite, covalent compounds are bad conductors of electricity.
(iv) Covalent compounds are soluble in non polar solvents (usually organic solvents). Polar covalent compounds are however soluble in polar solvents.
(v) Covalent compounds contain molecules and they undergo reactions slowly.
(vi) Many covalent compounds exhibit various types of isomerism.
Q. 6. (i) Name the charged particles which attract one another to form electrovalent compounds.
Answer
(i) Cation and anion
(ii) There is mutual sharing of electrons to form a covalent compound.
(iii) 2
(iv) Magnesium is oxidised and chlorine is reduced.
Q. 7. In the formation of compound XY2, atom X gives one electron to each Y atom. What is the nature of bond to XY2 ? Give four properties of XY2.
Answer
The bond in XY2 is ionic.
Properties :
(i) It is hard and brittle.
(ii) It is soluble in water.
(iii) It has high melting and boiling point.
(iv) It does not conduct electric current in the solid state but conducts electric current in the molten or dissolved state.
Q.8. (i) Give one property of hydrogen chloride which agrees with it being a covalent compound.
Answer
(i) Hydrogen chloride is a gas at room temperature and in dry state it is a bad conductor of electricity.
(ii) Magnesium chloride in the molten state or in aqueous solution is a good conductor of electricity and therefore is an ionic compound.
(iii) Hydrogen chloride.
(iv) Hydrogen chloride is a gas. In dry state, it is bad conductor of electricity. Hence, it is a covalent compound.
Q. 9. What are the characteristics of coordinate compounds ?
Answer
The general characteristics of coordinate compounds are as follows :
(i) Coordinate compounds are identical to normal covalent compounds.
(ii) It is rigid and has directional properties.
(iii) These compounds are soluble in non-polar solvents and insoluble in polar solvent.
(iv) These compounds behave as non-conductors of electricity.
(v) The melting and boiling points are higher than covalent compounds and lower than ionic compounds.
(vi) These are stable compounds.
Q. 10. Which conditions are necessary for the formation of coordinate bond ?
Answer
For the formation of a coordinate bond the atom acting as a donor must have one unshared pair of electrons which may be donated by it to the acceptor atom. The acceptor atom must have an empty orbital to accept the lone pair of electrons.
Q. 11 What is lone pair effect ? In what kind of compound does this effect occur ?
Answer
When the unshared pair of electrons around an atom in the middle of a molecule is completely shared by another atom or an ion, it is called lone pair effect. Lone pair effect is shown by polar covalent compounds such as HCl and NH3.
