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INTERNATIONAL INDIAN SCHOOL RIYADH
WORKSHEET FIRST TERM (CLASS -XI)
CHEMISTRY
UNIT -1
SOME BASIC CONCEPTS IN CHEMISTRY
1. Define one atomic mass unit .
2. Define a)molar mass b)molar volume
3. What is a limiting reagent.?
4. Define molarity .Give its SI unit.
5. Define one mole.
6. What is the value of Avogadro constant?
7. Define molality. Why molality is preferred over molarity.?
8. Define empirical formula and molecular formula.
9. What will be the mass of one C12 atom.?
10.What is the difference between Molarity and Molality.
11.What is the mass of 3 gram atoms of calcium?
12.Calculate the molar mass of Glucose(C6H12O6)
13.Define Gram molecular mass ,formula mass.
14.How is molecular formula related to empirical formula. Give suitable
example
15.20 gm of glucose dissolved in 200g of water to prepare a solution.
Calculate the mass percentage of glucose in the solution.
16.A solution is prepared by dissolving 5.85g of NaCl in 90g of H2O. Find
mole Fraction of NaCl and H2O.
17.Calculate the mass of CaCO3, which is required to react with 25 ml of 0.75
M HCl., according to the equation
18.Calculate the amount of potassium chlorate required to prepare 2.4
moles of oxygen.
(2KClO3 2KCl+3O2)
19.An organic compound on investigation gave 52.2%carbon,13.0%
hydrogen,and rest oxygen .Find the empirical formula of the compound
(Ans:C2H6O).
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20.Empirical formula of a compound X (Molar mass = 78 mol-1) is CH. Write
its molecular formula.
21.Which has more number of atoms ? 1.0 g Na or 1.0 g Mg.
22.How are 0.5 mol Na2CO3 and 0.5 M Na2CO3 different from each other ?
23.The cost of table salt ( NaCl ) is Rs. 10 per Kg. calculate its cost per mole. (
Molar mass of NaCl is 58.5 gmol-1
24.Calculate the percentage of N in urea. (Molar mass of urea = 60 g mol-1
25.Give one example each of a molecule in which empirical formula and
molecular formula is (i) Same (ii) Different
26.The density of 3 M solution of NaCl is 1.25 g mL-1. Calculate molality of the
solution.
27.The reaction 2C + O2 —→ 2CO
is carried out by taking 24.0 g of carbon and 96.0 g of O2. Find out. (i)
Which reactant is left in excess ? (ii) How much of it is left ? (iii) How many
grams of the other reactant should be taken so that nothing is left at the
end of the reaction ?
28.Zinc and hydrochloric acid react according to the reaction:
Zn(s) + 2HCl(aq) —→ ZnCl2(aq) + H2(g)
If 0.30 mol Zn are added to hydrochloric acid containing 0.52 mol of HCl,
How many moles of H2 are produced ?
29.The Molarity of a solution of sulphuric acid is 1.35 M. Calculate its
molality. (The density of acid solution is 1.02 g cm–3).
WORK SHEET
UNIT 2 -STRUCTURE OF ATOM
1. Distinguish between a photon and a quantum.
2. The line spectrum of an element is known as fingerprints of its atom.
Comment.
3. What is the value of the Bohr’s radius for the third orbit of hydrogen
atom?
4. Which series of lines of the hydrogen spectrum lie in the visible region’?
5. In building up of the atoms the filling of 4s orbital takes place before the
3d orbital. Why?
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6. Why did Heisenberg’s uncertainty principle replace the concept of
definite orbit by the concept of probability?
7. Can a moving cricket ball have a wave character ? Justify your answer.
8. Heisenberg uncertainty principle has no significance in our everyday
life.Explain.
9. What are the four quantum numbers of 19th electron of copper ?
(Given : Atomic number of copper = 29)
10.How many radial and angular nodes are present in 2p orbital.
11.Give the essential postulates of Bohr’s model of an atom. How did it
explain origin of the spectral lines in H-atom ?
12.Distinguish between Absorption and emission spectrum.
13.State (i) Aufbau principle (ii) Pauli’s principle (iii) Hund’s rule.
14.List the differences between orbit and orbital .
15.Write down the electronic configuration of Fe3+ and Ni2+. How many
unpaired electrons are present? (Given Atomic number, Fe = 26, Ni = 28).
16.What is the Hund’s rule of maximum multiplicity ? Explain with suitable
example.
17.State Heisenbergs uncertainty principle. Give its mathematical
expression. Also give its significance.
18.Explain why :
(a) The three electrons present in 2p subshell of nitrogen remain unpaired.
(b) Cr has configuration 3d5 4s1 and not 3d4 4s2.
19.Define the following terms :
(i) Threshold frequency (ii) Work function.
20.State de Broglie equation. Write its significance.
21.What are the draw backs of Bohr’s atomic model?
22.What is stark effect/zeeman effect
23.Draw the shapes of the following orbitals.
(i) 3dxy (ii) dz2
24.What is the total number of orbitals associated with the principal
quantum number n = 3 ?
25.. Give the quatum numbers for the valency electrons of nitrogen atom.
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26.State (n+l) rule with an example
27.Using s, p, d, f notations, describe the orbital with the following quantum
numbers:-
n = 3, l = 0, (b) n = 4, l = 2, (c) n = 5, l = 3, (d) n = 1, l = 0
28.Write the electronic configurations of the following ions :
(a) H– (b)Na+ (c)O2– (d) F–
29.I)The unpaired electrons in Al and Si are present in 3p orbital. Which
electrons will experience more effective nuclear charge from the nucleus?
(ii) Indicate the number of unpaired electrons in: (a) P, (b) Si, (c) Cr, (d) Fe
30.Which of the following orbitals are not possible? 1p, 2s, 3f and 4d
31.How many electrons in an atom may have the following quantum number
a)n = 4, ms = – ½ (b) n = 3, l = 0
Numerical
1. Calculate the number of protons emitted in 10 hours by a 60 W sodium
lamp emitting radiations of wavelength 6000 Å.
2. A 100 watt bulb emits monochromatic light of wavelength 400 nm.
Calculate the number of protons emitted per second by the bulb.
3. What should be the ratio of velocities of CH4 and O2 molecules so that
they are associated with de Broglie waves of equal wavelength ?
4. Calculate the wavelength of a tennis ball of mass 60 gm moving with a
velocity of 10 m per second. (h = 6.626 × 10–34 kg m2 s–1)
5. (a) What is de-Broglie wavelength for an electron moving with velocity of
light?
(b) What is the angular momentum of electron in 5th shell?
6. Electrons are emitted with zero velocity from a metal surface when it is
exposed to radiation of wavelength 6800 Å. Calculate threshold frequency
(νo) and work function (Wo ) of the metal.
7. The work function for caesium atom is 1.9 eV. Calculate (a) the threshold
wavelength and (b) the threshold frequency of the radiation. If the
caesium element is irradiated with a wavelength 500 nm, calculate the
kinetic energy and the velocity of the ejected photoelectron.
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8. What is the wavelength of light emitted when the electron in a hydrogen
atom undergoes transition from an energy level with n = 4 to an energy
level with n = 2?
9. i)Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.
10.The energy associated with the first orbit in the hydrogen atom is -2.18 x
10-18J/atom. i)What is the energy associated with the fifth orbit
(ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.
UNIT-3
CLASSIFICATION OF ELEMENTS AND PERIODICITY IN PROPERTIES
Question 1.
The chemistry of lithium is very similar to that of magnesium even though
they are placed in different groups. Its reason is:
(a) Both are found together in nature
(b) Both have nearly the same size
(c) Both have similar electronic configuration
(d) The ratio of their charge and size (charge density) is nearly the same
Question 2.
The element with atomic number 35 belongs to
(a) d – Block (b) f – Block (c) p – Block (d) s – Block
Question 3.
The correct order of first ionization potential among following elements, Be,
B, C, N and O is
(a) B < Be < C < O < N (b) B < Be < C < N < O
(c) Be < B < C < N < O (d) Be < B < C < O < N
Question 4.
Representative elements are those which belong to
(a) p and d – Block (b) s and d – Block (c) s and p – Block
(d) s and f – Block
Question 5.
Which of the following properties generally decreases along a period?
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(a) Ionization Energy (b) Metallic Character(c) Electron Affinity
(d) Valency.
Question 6.
On the Paulings electronegativity scale the element next to F is
(a) N (b) Cl (c) O (d) Ne.
Question 7.
The group number, number of valence electrons, and valency of an element
with the atomic number 15, respectively, are:
(a) 16, 5 and 2 (b) 15, 5 and 3
(c) 16, 6 and 3 (d) 15, 6 and 2
Question 8.
Which of the following oxides is amphoteric in character?
(a) SnO2 (b) CO2 (c) SiO2 (d) CaO
Question 9.
In the modern periodic table, the period indicates the value of:
(a) Atomic Number (b) Atomic Mass
(c) Principal Quantum Number (d) Azimuthal Quantum Number
Question 10.
In the long form of the periodic table, the valence shell electronic
configuration of 5s²5p4 corresponds to the element present in:
(a) Group 16 and period 6 (b) Group 17 and period 6
(c) Group 16 and period 5 (d) Group 17 and period 5
Question 11.
Arrange S, O and Se in ascending order of electron affinity
(a) Se < S < O (b) Se < O < S (c) S < O < Se (d) S < Se < O
Question 12.
In the modern periodic table , the period indicates the value of:
(a) Atomic Number (b) Atomic Mass
(c) Principal Quantum Number (d) Azimuthal Quantum Number
Question 13.
The electronic configuration of an element is 1s², 2s² 2p6, 3s² 3p³. What is
the atomic number of the element which is just below the above element in
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the periodic table
(a) 31 (b) 34 (c) 33 (d) 4
Question 14.
The reduction in atomic size with increase in atomic number is a
characteristic of elements of-
(a) d−block (b) f−block (c) Radioactive series (d) High atomic masses
Question 15.
The number of elements in the 5th period of the periodic table is
(a) 3 (b) 9 (c) 8 (d) 18
Question 16.
The electronic configuration of halogen is
(a) ns² np6 (b) ns² np3 (c) ns² np5 (d) ns²
Question 17.
Which of the following forms the most stable gaseous negative ion?
(a) F (b) Cl (c) Br (d) I
Question 18.
On the Paulings electro negativity scale the element next to F is
(a) N (b) Cl (c) O (d) Ne.
Question 19.
The element californium belongs to a family of :
(a) Alkali metal family (b) Actinide series
(c) Alkaline earth family (d) Lanthanide series
Question 20.
Increasing order of electro negativity is
(a) Bi < P < S < C (b) P < Bi < S < Cl
(c) S < Bi < P < C (d) Cl < S < Bi < PN
Q.21.
The chemistry of lithium is very similar to that of magnesium even though
they are placed in different groups. Its reason is:
(a) Both are found together in nature
(b) Both have nearly the same size
(c) Both have similar electronic configuration
(d) The ratio of their charge and size (i.e. charge density)is nearly the same
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Q.22. The electronic configuration of halogen is
(a) ns² np6 (b) ns² np3 (c) ns² np5 (d) ns²
Q.23. The order of increasing sizes of atomic radii among the
elements O, S, Se and As is :
(a) As < S < O < Se (b) Se < S < As < O
(c) O < S < As < Se (d) O < S < Se < As
24.How does the electronic configuration of an atom of an element relate to its
position in the modern periodic table? Explain with one example.
25.The atomic numbers of three elements, X, Y and Z are 9,11 and 17 respectively.
Which two of these elements will show similar chemical properties? Why?
26.In the periodic table, how does the tendency of atoms to lose electrons change
on going from left to right across a period? top to bottom in a group?
(a) How are the following related?
Number of valence electrons of different elements in the same group.
Number of shells of elements in the same period.
(b) How do the following change?
Number of shells of elements as we go down a group.
Number of valence electrons of elements on moving from,left to right in a
period. Atomic radius in moving from left to right along a period.
Atomic size down a group.
27. a)What is the difference between the terms electron gain enthalpy and
electronegativity?
b) Arrange the following in increasing order of their size;
O2-,Mg2+,Na+,N3-,F-, Al3+
29.Assign reason for the following.
a). Be has higher ionization enthalpy than B.
b). Ionisation enthalpy of N is higher than that of O.
c). Electron gain enthalpy of F is less negative than Cl.
d).The size of an anion is larger than that of parent atom.
UNIT-4
CHEMICAL BONDING AND MOLECULAR STRUCTURE
Question 1.
The hybrid state of sulphur in SO2 molecule is :
(a) sp² (b) sp³ (c) sp (d) sp³d
Question2.
Which one of the following does not have sp² hybridised carbon?
(a) Acetone (b) Acetic acid (c) Acetonitrile (d) Acetamide
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Question 3
Find the molecule with the maximum dipole moment
(a) CH4 ( b) NH3 (c) CO2 (d) NF3
Question 4
Which one has a pyramidal shape?
(a) SO3 (b) PCl3 (c) CO32 (d) NO3–
Question 5.
The outer orbitals of C in ethene molecule can be considered to be hybridized
to give three equivalent sp² orbitals. The total number of sigma (s) and pi (p)
bonds in ethene molecule is
(a) 1 sigma (s) and 2 pi (p) bonds (b) 3 sigma (s) and 2 pi (p) bonds
(c) 4 sigma (s) and 1 pi (p) bonds (d) 5 sigma (s) and 1 pi (p) bonds
Question 6.
Which of the following is a linear molecule?
(a) ClO2 (b) CO2 (c) NO2 (d) SO2
Question 7
Using VSEPR theory, predict the species which has square pyramidal shape
(a) SnCl2 (b) CCl4 (c) SO3 (d) BrF5
Question 8
Which of the following statements is not correct ?
(a) Double bond is shorter than a single bond
(b) Sigma bond is weaker than a pi bond
(c) Double bond is stronger than a single bon
(d) Covalent bond is stronger than hydrogen bond
Question 9
Which of the following statements about water is not correct?
1. Water molecules contain covalent bonds.
2. Water has weak forces between molecules.
3. Water has a low melting point.
4. Water molecules contain H+ and OH- ions.
Question 10
Which of the following gives the best explanation for why a substance does not
conduct electricity?
A. The bonding in the substance is not ionic.
B. The bonding model in the substance does not have free electrons
C. The bonding model does not have ions which are free to move, or free electrons.
D. The bonding model does not have ions or free electrons.
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11.Define hydrogen bond.Is it weaker or stronger than van der waals force?
12.Use molecular orbital theory to explain Be2 molecule does not exist.
13.Which out NF3 or NH3 has higher dipole moment and Why?
14.Distinguish between a sigma bond and pi bond.
15.What is meant by hybridization of atomic orbitals?
16.Explain the formation of H2 molecule on the basis of valence bond theory.
17.Describe the hybridization in case of SF6.
18.Calculate the bond order of N2,O2,O2+ and O2-
19.Explain polar covalent bond with the help of an example.
20.Write the resonance structures for SO3,NO2 and CO2
Chemistry Topics
Mathematics Class 10 ICSE SolutionsCBSFollow us on Pinterest
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