CHEMISTRY REVISION SESSION ENDING EXAMS
SOME BASIC CONCEPTS OF CHEMISTRY
1 What do you mean by significant figures? What are rules for determining the number of significant figures?
2 How many significant figures are present in the following? (i) 0.0025 (ii) 208 (iii) 5005 (iv) 126,000 (v) 500.0 (vi)
2.0034
3 Round up the following upto three significant figures: (i) 34.216 (ii) 10.4107 (iii) 0.04597 (iv) 2808
4 Convert the following into basic units: (i) 28.7 pm (ii) 15.15 pm (iii) 25365 mg
5 State and illustrate the law of constant proportions.
6 State and explain the law of multiple proportions.
7 Calculate the molecular mass of the following: (i) H2O (ii) CO2 (iii) CH4(iv) C6H12O6
8 Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% Dioxygen by mass.
9 A compound contains 4.07 % hydrogen,24.27 % carbon and 71.65 % chlorine. Its molar mass is 98.96 g. What
are its empirical and molecular formulas ?
10 Define the following terms. (Write the mathematical formulas related to terms)(a) Mass percent (b) Molarity (c)
Molality (d) Mole-fraction (e) Mass percent
11 Calculate the mass of sodium acetate (CH3COONa) required to make 500 mL of 0.375 molar aqueous solution.
(Molar mass of sodium acetate is 82.0245 g mol–1).
12 Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the
mass per cent of nitric acid in it being 69%.
13 What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final
volume up to 2L?
14 A sample of drinking water was found to be severely contaminated with chloroform, CHCl 3, supposed to be
carcinogenic in nature. The level of contamination was 15 ppm (by mass).(i) Express this in percent by mass. (ii)
Determine the molality of chloroform in the water sample.
15 Calculate the number of atoms in each of the following (i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He.
16 Calculate the molarity of NaOH in the solution prepared by dissolving its 4 g in enough water to form 250 mL of
the solution.
17 How does molality & Molarity depend on temperature? Out of molality & Molarity which one is better way to
express concentration?
STRUCTURE OF ATOM
1 The number of electrons, protons and neutrons in a species are equal to 18,16 and 16 respectively. Assign the
proper symbol to the species.
2 Which of the following are isoelectronic species i.e., those having the same number of electrons? Na +, K+, Mg2+,
Ca2+, S2–, Ar.
3 Define the terms Atomic Number, Mass Number, Isobars, Isotopes
4 Define the terms frequency wavelength & wave number (Write mathematical forms also).
5 Yellow light emitted from a sodium lamp has a wavelength of 580 nm. Calculate the frequency and
wavenumber of the yellow light.
6 . Write a note on the Spectral Lines for Atomic Hydrogen.
7 Calculate the energy associated with the first orbit of He + .What is the radius of this orbit?
8 The energy associated with first orbit in the hydrogen atom is –2.18 × 10 –18J atom–1. What is the energy
associated with the fifth orbit? (ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.
9 Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.
10 Explain Dual behaviour of matter. State de Broglie’s relation. Give its mathematical expression.
11 What will be the wavelength of a ball of mass 0.1 kg moving with a velocity of 10 m s –1?
12 The mass of an electron is 9.1 X 10–31kg. If its K.E. is 3.0 X 10–25 J, calculate its wavelength.
13 State Heisenberg’s Uncertainty Principle. Give its mathematical expression.
14 A microscope using suitable photons is employed to locate an electron in an atom within a distance of 0.1 Å.
What is the uncertainty involved in the measurement of its velocity?
15 Using s, p, d, f notations, describe the orbital with the following quantum numbers(a) n = 2, l = 1, (b) n = 4, l = 0,
(c) n = 5, l = 3, (d) n = 3, l = 2 (e) n=1, l=0 (f) n = 3 l=1 (g) n = 4; l =2 (h) n= 4; l=3.
16 What is the total number of orbitals associated with the principal quantum number n = 3 ?
17 What is the lowest value of n that allows g orbitals to exist?
MAHENDRA KALRA ENJOY CHEMISTRY
, 18 An electron is in one of the 3d orbitals. Give the possible values of n, l and m l for this electron.
19 An atomic orbital has n = 3. What are the possible values of l and m l ?
20 How many sub-shells are associated with n = 4?
21 Which of the following orbitals are possible? 1p, 2s, 2p ,2d, 4f ,6d and 3f.
22 How many electrons in an atom may have the following quantum numbers? (a) n = 4, m s = – ½ (b) n = 3, l = 0
23 State (n+l) rule Aufbau rule & Pauli rule.
24 .Expalin the exceptional configuration of copper and chromium.
25 Give the electronic configurations of the following ions: Cu2+ Cr3+ Fe2+ S2- Fe2+ O2- Na+
26 Explain Hunds rule of maximum multiplicity with an example.
27 Indicate the number of unpaired electrons in : (a) P, (b) Si, (c) Cr, (d) Fe and (e) Kr.
28 An atom of an element contains 29 electrons and 35 neutrons. Deduce (i) the number of protons and (ii) the
electronic configuration of the element.
29 Draw the shapes of s,p,d & f orbitals.
CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES
1 What would be the IUPAC name and symbol for the elements with atomic number 101 to 120?
2 The element with atomic number 119 has not been discovered. What would be the IUPAC name and symbol of
this element?
3 Give the electronic configuration and in terms of period group and block where would you locate the elements
with Z= 17, 19. 24,26,29 31,34,38, 40, 51,55,114 ,117 and 120 ?
4 How does the atomic radius vary in a period and in a group? How do you explain the variation?
5 Explain why cations are smaller and anions larger in radii than their parent atom? OrDescribe the theory
associated with the radius of an atom as it (a) gains an electron (b) Loses an electron
6 What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the
following atoms or ions.(i)F- (ii)Ar (iii)Mg+2 (iv)Rb+
7 Consider the following species: N3-,O2-, Na+,Mg+2, and Al+3 (a)What is common in them? (b)Arrange them in the
order of increasing ionic radii.
8 Arrange the following in order of increasing radii: (a)N,O,P (b)F,Cl,Br (c)I-,I,I+
9 Which of the following species will have the largest and the smallest size Mg, Mg 2+, Al, Al3+.
10 How does the Ionization vary in a period and in a group? How do you explain the variation?
11 Among the second period elements the actual ionization enthalpies are in the order Li<B<Be<C<O<N<F<Ne
Explain why (i) Be has higher ionization enthalpy than B. (ii)O has lower ionization enthalpy than N and F?
12 How would you explain the fact the first ionization enthalpy of sodium is lower than that of Magnesium but its
second ionization enthalpy is higher than that of Magnesium?
13 How does the electron gain enthalpy in a period and in a group? How do you explain the variation?
14 Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the
first? Justify your answer?
15 Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) O or F (ii)F or
Cl (iii) O or S.Give reason to support your answer
16 What is the difference between the terms electron gain enthalpy and electronegativity?
17 Show by a chemical reaction with water that Na2O is a basic oxide and Cl2O7 is an acidic oxide.
Chemical bonding and Molecular Structure
1. Define Covalent Bond. Explain its types with examples.
2. Draw the Lewis structures for the following molecules & ions: H2S, SiCl4, BeF2, CO32−, BeCl2, BCl3,
SiCl4, AsF5,H2S,PH3,PCl5,SF6,NH3,SF4,ClF3,BrF5,XeF4,NO3-
3. What is Formal Charge? Calculate the formal charge on all elements of O3 & CO32−.
4. Define Electrovalent Bond or Ionic Bond. Write the favorable factors for the formation of ionic bond.
5. Is CaF2 linear or bent or neither of the two ? Justify.
6. Use Lewis symbols to show electron transfer between the following atoms to form Cations and anions: (a)
K and S (b) Ca and O (c) Al and N (d)Al and O
7. Define octet rule. Write its significance and limitations.
8. Discuss the shape using the VSEPR model: H2S, SiCl4, BeF2, CO32−, BeCl2, BCl3, SiCl4, AsF5, H2S,
PH3,PCl5,SF6,NH3,SF4,ClF3,BrF5,XeF4,NO3-
9. Draw the structure of the following : (i) BrF3 (ii) XeO3
MAHENDRA KALRA ENJOY CHEMISTRY
SOME BASIC CONCEPTS OF CHEMISTRY
1 What do you mean by significant figures? What are rules for determining the number of significant figures?
2 How many significant figures are present in the following? (i) 0.0025 (ii) 208 (iii) 5005 (iv) 126,000 (v) 500.0 (vi)
2.0034
3 Round up the following upto three significant figures: (i) 34.216 (ii) 10.4107 (iii) 0.04597 (iv) 2808
4 Convert the following into basic units: (i) 28.7 pm (ii) 15.15 pm (iii) 25365 mg
5 State and illustrate the law of constant proportions.
6 State and explain the law of multiple proportions.
7 Calculate the molecular mass of the following: (i) H2O (ii) CO2 (iii) CH4(iv) C6H12O6
8 Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% Dioxygen by mass.
9 A compound contains 4.07 % hydrogen,24.27 % carbon and 71.65 % chlorine. Its molar mass is 98.96 g. What
are its empirical and molecular formulas ?
10 Define the following terms. (Write the mathematical formulas related to terms)(a) Mass percent (b) Molarity (c)
Molality (d) Mole-fraction (e) Mass percent
11 Calculate the mass of sodium acetate (CH3COONa) required to make 500 mL of 0.375 molar aqueous solution.
(Molar mass of sodium acetate is 82.0245 g mol–1).
12 Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the
mass per cent of nitric acid in it being 69%.
13 What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final
volume up to 2L?
14 A sample of drinking water was found to be severely contaminated with chloroform, CHCl 3, supposed to be
carcinogenic in nature. The level of contamination was 15 ppm (by mass).(i) Express this in percent by mass. (ii)
Determine the molality of chloroform in the water sample.
15 Calculate the number of atoms in each of the following (i) 52 moles of Ar (ii) 52 u of He (iii) 52 g of He.
16 Calculate the molarity of NaOH in the solution prepared by dissolving its 4 g in enough water to form 250 mL of
the solution.
17 How does molality & Molarity depend on temperature? Out of molality & Molarity which one is better way to
express concentration?
STRUCTURE OF ATOM
1 The number of electrons, protons and neutrons in a species are equal to 18,16 and 16 respectively. Assign the
proper symbol to the species.
2 Which of the following are isoelectronic species i.e., those having the same number of electrons? Na +, K+, Mg2+,
Ca2+, S2–, Ar.
3 Define the terms Atomic Number, Mass Number, Isobars, Isotopes
4 Define the terms frequency wavelength & wave number (Write mathematical forms also).
5 Yellow light emitted from a sodium lamp has a wavelength of 580 nm. Calculate the frequency and
wavenumber of the yellow light.
6 . Write a note on the Spectral Lines for Atomic Hydrogen.
7 Calculate the energy associated with the first orbit of He + .What is the radius of this orbit?
8 The energy associated with first orbit in the hydrogen atom is –2.18 × 10 –18J atom–1. What is the energy
associated with the fifth orbit? (ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.
9 Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.
10 Explain Dual behaviour of matter. State de Broglie’s relation. Give its mathematical expression.
11 What will be the wavelength of a ball of mass 0.1 kg moving with a velocity of 10 m s –1?
12 The mass of an electron is 9.1 X 10–31kg. If its K.E. is 3.0 X 10–25 J, calculate its wavelength.
13 State Heisenberg’s Uncertainty Principle. Give its mathematical expression.
14 A microscope using suitable photons is employed to locate an electron in an atom within a distance of 0.1 Å.
What is the uncertainty involved in the measurement of its velocity?
15 Using s, p, d, f notations, describe the orbital with the following quantum numbers(a) n = 2, l = 1, (b) n = 4, l = 0,
(c) n = 5, l = 3, (d) n = 3, l = 2 (e) n=1, l=0 (f) n = 3 l=1 (g) n = 4; l =2 (h) n= 4; l=3.
16 What is the total number of orbitals associated with the principal quantum number n = 3 ?
17 What is the lowest value of n that allows g orbitals to exist?
MAHENDRA KALRA ENJOY CHEMISTRY
, 18 An electron is in one of the 3d orbitals. Give the possible values of n, l and m l for this electron.
19 An atomic orbital has n = 3. What are the possible values of l and m l ?
20 How many sub-shells are associated with n = 4?
21 Which of the following orbitals are possible? 1p, 2s, 2p ,2d, 4f ,6d and 3f.
22 How many electrons in an atom may have the following quantum numbers? (a) n = 4, m s = – ½ (b) n = 3, l = 0
23 State (n+l) rule Aufbau rule & Pauli rule.
24 .Expalin the exceptional configuration of copper and chromium.
25 Give the electronic configurations of the following ions: Cu2+ Cr3+ Fe2+ S2- Fe2+ O2- Na+
26 Explain Hunds rule of maximum multiplicity with an example.
27 Indicate the number of unpaired electrons in : (a) P, (b) Si, (c) Cr, (d) Fe and (e) Kr.
28 An atom of an element contains 29 electrons and 35 neutrons. Deduce (i) the number of protons and (ii) the
electronic configuration of the element.
29 Draw the shapes of s,p,d & f orbitals.
CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES
1 What would be the IUPAC name and symbol for the elements with atomic number 101 to 120?
2 The element with atomic number 119 has not been discovered. What would be the IUPAC name and symbol of
this element?
3 Give the electronic configuration and in terms of period group and block where would you locate the elements
with Z= 17, 19. 24,26,29 31,34,38, 40, 51,55,114 ,117 and 120 ?
4 How does the atomic radius vary in a period and in a group? How do you explain the variation?
5 Explain why cations are smaller and anions larger in radii than their parent atom? OrDescribe the theory
associated with the radius of an atom as it (a) gains an electron (b) Loses an electron
6 What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the
following atoms or ions.(i)F- (ii)Ar (iii)Mg+2 (iv)Rb+
7 Consider the following species: N3-,O2-, Na+,Mg+2, and Al+3 (a)What is common in them? (b)Arrange them in the
order of increasing ionic radii.
8 Arrange the following in order of increasing radii: (a)N,O,P (b)F,Cl,Br (c)I-,I,I+
9 Which of the following species will have the largest and the smallest size Mg, Mg 2+, Al, Al3+.
10 How does the Ionization vary in a period and in a group? How do you explain the variation?
11 Among the second period elements the actual ionization enthalpies are in the order Li<B<Be<C<O<N<F<Ne
Explain why (i) Be has higher ionization enthalpy than B. (ii)O has lower ionization enthalpy than N and F?
12 How would you explain the fact the first ionization enthalpy of sodium is lower than that of Magnesium but its
second ionization enthalpy is higher than that of Magnesium?
13 How does the electron gain enthalpy in a period and in a group? How do you explain the variation?
14 Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the
first? Justify your answer?
15 Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) O or F (ii)F or
Cl (iii) O or S.Give reason to support your answer
16 What is the difference between the terms electron gain enthalpy and electronegativity?
17 Show by a chemical reaction with water that Na2O is a basic oxide and Cl2O7 is an acidic oxide.
Chemical bonding and Molecular Structure
1. Define Covalent Bond. Explain its types with examples.
2. Draw the Lewis structures for the following molecules & ions: H2S, SiCl4, BeF2, CO32−, BeCl2, BCl3,
SiCl4, AsF5,H2S,PH3,PCl5,SF6,NH3,SF4,ClF3,BrF5,XeF4,NO3-
3. What is Formal Charge? Calculate the formal charge on all elements of O3 & CO32−.
4. Define Electrovalent Bond or Ionic Bond. Write the favorable factors for the formation of ionic bond.
5. Is CaF2 linear or bent or neither of the two ? Justify.
6. Use Lewis symbols to show electron transfer between the following atoms to form Cations and anions: (a)
K and S (b) Ca and O (c) Al and N (d)Al and O
7. Define octet rule. Write its significance and limitations.
8. Discuss the shape using the VSEPR model: H2S, SiCl4, BeF2, CO32−, BeCl2, BCl3, SiCl4, AsF5, H2S,
PH3,PCl5,SF6,NH3,SF4,ClF3,BrF5,XeF4,NO3-
9. Draw the structure of the following : (i) BrF3 (ii) XeO3
MAHENDRA KALRA ENJOY CHEMISTRY
