Week -1
CHEMISTRY
(Language of Chemistry, Chemical Reaction)
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Question 1. (Any Three). 1x3= 3
Classify the following reactions
i) Zn(s) + H₂SO₄(aq)-->ZnSO₄+ H₂ (g)
ii) BaCl₂(aq)+ Na₂SO₄(aq) --> BaSO₄(s) + 2NaCl(aq)
iii) 2CO(g) + O₂(g) ---> 2CO₂(g)
Iv) 2KNO₃(s) ---> 2KNO₂(l)+ O₂(g)
Question 2 (Any Three) 2x3 = 6
Define:
i) Chemical double decomposition
ii) Catalyst
iii) Oxidising agent
iv) Inflammable substance
Question 3. (2)
CuO(s)+ H₂(g)--------Cu(s)+ H₂O(l).
In the above reaction, by giving reasons, explain which substance is:
i) Oxidised
ii) Reduced
iii) Oxidising agent
iv) Reducing agent
OR
Write the formula of the following:
i) Ammonium sulphate
ii) Zinc carbonate
iii) Lead hydroxide
iv) Barium chooride
Question 4. (3x1)
State the valency and formula of the following:
i) Ammonia
ii) calcium
iii) Ferric
Question 5. 1x3 = 3
Write the formula and then balance the following equations:
i) Ammonium chloride --> Ammonia+ Hydrogen chloride
ii) Red lead oxide --> lead monoxide+ Oxygen
iii) Sodium nitrate --> sodium nitrite+ Oxygen.
Question 6. (1)
XCl₂ is the chloride of metal X. Write down the formula of sulphate and hydroxide.
Question 7. (2)
What is the difference between Exothermic and Endothermic reaction.
CLASS- IX
PHYSICS
F. M- 100. Time: 2 hrs
1) a) State any four difference between distance and displacement.
b) Give an example of the motion of a body moving with a constant speed, but with variable velocity. Draw a diagram to represent such a motion.
c) A car is moving with a velocity of 72 kmph. The brakes are applied to retard at a rate of 2 m/s². What will be the velocity after 5s of applying the brakes ? (4+3+3)
2) From the velocity-time graph derive the equation of motion, ut + (1/2) at².
b) Following table gives the displacement of a car at different instants of time. Draw the displacement-time sketch and find the average velocity of the car. What will be the displacement of the car at 2.5s and 4.5 s?
Time (s): 0 1 2 3 4
displacement(m): 0 5 10 15 20 (5+5)
3) A spacecraft flying in a straight course with a velocity of 75 kmph fires its rocket motors for 6s. At the end of this time its speed is 120 kmph in the same direction. Find
i) the spacecraft's average acceleration while the motors were firing.
ii) the distance travelled by the space craft in the first 10s after the rocket motors were started, the motors having been in action for only 6.0s.
b) Derive the mathematical form (F= ma) of Newton's second law of motion. (5+5)
4) a) Use Newton's second law of motion to explain the following:
i) you pull your hands back while catching a fast moving cricket ball.
ii) you prefer to land on sand instead of hard floor while taking a high jump.
b) Obtain the relationship between S. I and C. G. S units of force.
c) A car is moving with a uniform velocity 30m. It is stopped in 2s by applying a force of 1500N through its breaks. Calculate
a) the changes in momentum of the car.
b) the retardation produced in car
c) the mass of car. (4+3+3)
5) a) State Newton's law gravitation. Write an expression for the gravitational force of attraction between two bodies of masses x and y separated by a distance r. Write the numerical value of gravitational constant G with its Si unit.
b) Name and state the action and reaction in the following cases:
i) firing a bullet from a gun.
ii) a book lying on a table.
iii) a person walking on the floor.
c) Define the term acceleration due to gravity. Write its SI unit. Write an expression to show is the acceleration due to gravity related to the mass and radius of the earth. (4+3+3)
6) a) State four differences between mass and weight.
b) A body of mass 10kg is taken from the Earth to the Moon. if the value of 'g' on the earth 9.8 m/s and on the moon is 1.6 m/s find :
i) the weight of the body on the earth.
ii) the mass and weight of the body on the Moon.
c) State 3 differences between thrust and pressure . (4+3+3)
7) a) Deduce an expression for the pressure at a depth inside a liquid.
b) Explain why a gas bubble released at the bottom of a lake grows in size as it rises to the surface of the lake.
c) Calculate the height of a water column which will exert on its base the same pressure as 70 cm column of mercury. Density of mercury is 13.6 x 10² kg/m³. (4+3+3)
8) a) State two factors which affect the atmospheric pressure as we go up. Draw an approximate graph to show the variation of atmospheric pressure with attitude.
b) Name and state the law of transmission of pressure in fluids.
c) What do the following indicate in a barometer regarding weather:
i) gradual fall in the Mercury level.
ii) sudden fall in the Mercury level.
iii) gradual rise in the Mercury level. (4+3+3)
9)a) State four differences between heat and the temperature.
b) What do you mean by anamalous expansion of water ? At what temperature the density of water is maximum ? State its value.
c) Draw a diagram showing the temperature of the various layers of water in an ice covered pond. (4+3+3)
10)a) When a bar of iron 50.0 cm long at 15°C is heated in a furnace, it becomes 50.4cm. If the coefficient of linear expansion of iron 0.000011°C, find the temperature of the furnace.
b) What do you understand by zero on Kelvin scale? Write its value in 0°C. State one difference and one feature of similarity between the Celsius and Kelvin scales .
c) The body temperature of healthy person 98.6°F. Calculate the corresponding temperature on the Kelvin scale. (4+3+3)
CHEMISTRY (Final)
Time: 1 hr 30+ 10 mins reading time: Marks-80
GROUP -A
1) Name the principle metal, the composition and two uses for the following alloys.
a) magnalium
b) stainless steel
c) German silver
d) bronze
e) aluminium bronze
f) brass (3+4+3.5+3.5+3+3)
2) In the equation given below, state which reaction will proceed and which reaction will not proceed. Give a reason for your answer. (8)
a) Zn+ CuSO₄ ---> ZnSO₄+ Cu.
b) Cu+ FeSO₄ ---> CuSO₄ + Fe.
c) 3Mg+ 2AlCl₃ --> 3MgCl₂ + 2Al.
d) 2Al + 3ZnSO₄ ---> Al₂(SO₄)₃+ 3Zn.
3) State most important uses of the following non metals. (12)
i) carbon ii) Nitrogen iii) Oxygen iv) silicon v) Phosphorus vi) Sulphur
GROUP B
4) a) What is petroleum ? (2)
b) Name four major fractions obtained and one use of each when petroleum is refined ? (8)
5) a) How is lamp black prepared on a large scale. (7)
b) State three uses of lamp black . (3)
6) What do you understand by the following terms. 10)
a) Radioactivity
b) Radioactive substances
c) oxidation
d) calcilation of ore
e) roasting of ore
7) a) What is an alloy ? Why are alloys made. (4)
b) Name two noble metals and give two uses of each metal named by you. (4)
c) Calculate the amount of Calcium oxide formed from 2g of calcium metal (Ca=40, O= 16). (2)
THE PERIODIC TABLE
1) Complete the statements given below pertaining to different Chemists and their contributions towards classification of elements by chosing the correct words from the following list.
(Mendeleeff, Robert Boyle, Early Chemist, New land, Lavoisier, Doberenier, Carl Scheele, Moseley, Humphry Davy)
a) _______attempted to classify elements on basis of their properties, metallic and non metallic nature, valency etc, but the classification was discarded and atomic weight and not properties were considered for further classification .
b) ______ classified elements into groups of three on observing a relationship between atomic weights of certain elements and their properties. He arranged elements in increasing order of atomic weights in groups of three called triads.
c) ______ are arranged elements in series in ascending order of their atomic weights and suggested a resemblance between the eighth and first element similar to the 8th and first notes on a musical scale.
d) _______ arranged elements in increasing order of their atomic weights and observed that elements with similar properties appear at regular intervals on arrangement. Such properties are called periodic properties and are those which appear at regular intervals in a periodic table. Examples of such properties are valency, electronegativity, metallic and nonmetallic character.
e) _____ stated that atomic number and not atomic weight of an element should be taken into consideration for classification of elements .
f) _______'periodic law states that the physical and chemical properties of elements are periodic functions of their atomic weights.
g) ______arranged elements in increasing order of atomic numbers in seven horizontal rows called and 18 vertical columns called groups.
2) Name or state the following reference to Mendeleef's periodic table:
a) On what basis was the classification of elements made by Mendeleeff.
b) State the terms used for the following pertaining to Mendeleef's periodic table.
i) The horizontal rows of elements in the periodic table.
ii) The vertical columns of elements in the periodic table.
iii) The properties which repeat themselves at regular intervals in the periodic table.
c) State three contributions made by Mendeleef's which significantly helped to form the basis of the modern periodic table.
d) Give reasons why Mendeleeff periodic table was not completely accepted as the Modern periodic table.
3) Naior state the following pertaining to the Modern Periodic Table.
a) The fundamental characteristics of an element which formed the basis of classification of elements in the Modern Periodic Table.
b) The number of horizontal rows - periods in the table.
c) The number of vertical columns - groups in the table.
d) The period which contains only two elements.
e) The period which contains 8 elements each .
f) The period which contains element having stable electronic configuration 2,8,8.
g) The first element of the periodic table,
h) The type of elements present in the zero group of the periodic table.
i) The last element of the third short period.
j) The period which contains the lanthanide series which is situated at the bottom of the periodic table.
k) The group which are further divided into subgroups A and B.
4) Name or state the following pertaining to the elements of the periodic table.
a) The number of electron shell in the elements of periods one, two or three respectively.
b) The electronic configuration of the zero group element of period-1.
c) The number of valence electrons of the element in group IV of period-2 of the periodic table.
d) The valency of the elements of group IA, VIIA and zero group.
e) The group to which the elements carbon (at no. 6), nitrogen (at no, 7) and oxygen (at no 8) belong.
f) The period to which sulphur (at no 16) and chlorine (at no 17) belong.
g) The electronegative element from the element sodium, magnesium and sulphur.
h) The type of bonding seen in the oxide of the element in period-3, group IIIA.
i) An element in period-3, group VA whose chloride exists in two different physical states.
j) The groups of the periodic table which contains the alkali metals , alkaline earth metals and the halogens respectively.
k) The grouping name given to the type of elements present in groups
i) IB to VIIB and VIII
ii) IA to VIIA
l) The non metal positioned in group IA.
m) The series of chemically reactive metals of period -7 placed at the bottom of the periodic table.
n) The least electronegative elements from the elements chlorine, bromine and Iodine in group VIIA.
o) The element in period-2, group IA, which shows similarity with a divalent metal in period-3 group IIA.
p) The non metallic element in period-2 to which is diatomic and unreactive at ordinary temperatures.
5) State whether the following statements of true or false. If false rewrite the correct statement.
a) Element with similar outer electronic configuration are placed in the same period of the periodic table.
b) If properties of one member of a group is known the properties of other members of the group could be correlated due to similarity or gradation in properties of elements in a group.
c) Non metals occupy the upper right hard corner of the periodic table.
d) The two sub groups A and B accommodate elements with similar properties.
e) Properties of elements remain the same on moving from left to right in the modern periodic table,
f) Electronegativity and nonmetallic character of elements increases across a period from left to right and decreases down a group.
6) Write i) Electronic configuration ii) Group Assigned iii) Metallic/ nonmetallic iv) Electronegative/Electropositive of the following:
Element Atomic number
a) Hydrogen. 1
b) Carbon 6
c) Nitrogen 7
d) Oxygen 8
e) Sulphur 16
f) Chlorine 17
g) Lead 82
h) Bismuth 83
i) Polonium 84
j) Astatine 85
CHEMISTRY TERMINOLOGY - CHEMICAL REACTIONS
THE LANGUAGE OF CHEMISTRY
1) State the valency and name the ion or radical in each of the following cases given below (The first example is completed for you):
Electrical ent positive ions or radicals
Symbol/Valency Name
a) K¹⁺ Potassium
b) Na
c) H
d) NH₄
e) Ca
f) Mg
g) Zn
h) Ba
i) Ni
i) Co
j) Al
k) Cr
Variable valencies
a) Cu¹⁺
b) Cu
c) Hg¹⁺
d) Hg
e) Fe²⁺
f) Fe
g) Mn²⁺
h) Mn
i) Pb²⁺
j) Pb
k) Pt²⁺
l) Pt
Electrovalent negative ion or radicals
Symbol/valency Name
a) Cl¹⁻ Chloride
b) ClO₃
c) ClO
d) Br
e) I
f) OH
g) NO₂
h) NO₃
i) HCO₃
j) HSO₃
k) HSO₄
l) AlO₂
m) MnO₄
n) SO₃
o) SO₄
p) S
q) CO₃
r) O
s) CrO₄
t) Cr₂O₇
u) ZnO₂
v) PbO₂
w) PO₄
x) N
y) C
2) State the valency of each of the elements in the respective compounds:
a) Sulphur in (i) sulphur dioxide
ii) sulphur trioxide
b) Nitrogen in i) Nitrogen monoxide
ii) Nitrogen dioxide
iii) dinitrogen oxide
iv) dinitrogen pentoxide
c) Copper in i) cupric oxide
ii) Cuprous oxide
3) Give the formulas of the following compounds whose metallic radical exhibits variable valency.
a) Cupric nitrate.
b) Cuprous chloride.
c) Iron(II) sulphate.
d) Mercuric nitrate.
e) Plumbous chloride.
f) Stannous chloride.
g) Mangannic sulphate.
h) Platinic chloride.
i) Mercurous chloride.
j) Iron [II] nitrate.
4) Give the name of the compounds whose formulas are listed below:
a) HNO₂ ___
b) HCO₃ |
c) H₂C₂O₄. |
d) H₃PO₄ | --- Acids
e) CH₃COOH |
g) Al(OH)₃
h) CaSiO₃.
i) Na₂ZnO₂.
j) K₂CrO₄.
k) Mg₃N₂.
5) A chemical equation is a shorthand form for a chemical change
a) 2KClO₃ ---∆--> 2KCl + 3O₂.
i) In the above reaction name the reactant and the products.
ii) State what the arrow in between indicates.
6) Balance the following equations.
a) CuO+ NH₃ --> Cu + H₂O + N₂.
b) NH₃ + Cl₂ --> HCl + NCl₃.
c) Mg₃N₂ + H₂O --> Mg(OH)₂ + NH₃.
d) Pb₃O₄ + HCl --> PbCl₂ + H₂O + Cl₂.
e) Manganese [IV] + Hydrochloric acid --> Manganese (II) Chloride+ Water + Chlorine.
f) Potassium hydroxide + Chlorine --> Potassium chloride + Potassium hypochlorite + Water.
g) Ammonium dichromate --> Chromiumoxide + Water+ Nitrogen.
h) Potassium sulphite + Nitric acid --> Potassium nitrate+ Water+ Sulphur dioxide.
i) Iron [II] chloride + Water + Sulphur dioxide --> Iron [II] Chloride+ Sulphuric acid+ Hydrochloric acid.
j) Copper+ Sulphuric acid --> Copper sulphate + Water+ Sulphur dioxide.
k) Iron [III] oxide + Carbon monoxide --> Iron + Carbon dioxide.
l) Sodium sulphite+ Sulphuric acid --> Sodium sulphate+ Water+ Sulphur dioxide.
m) Zinc + Sodium hydroxide --> Sodium zincate --> Hydrogen.
n) Aluminium+ Carbon dioxide --> Aluminium oxide + Carbon.
o) Sodium bicarbonate+ Aluminium sulphate --> Sodium sulphate+ Aluminium hydroxide+ Carbon dioxide.
p) Calcium hydroxide+ Ammonium sulphate --> Calcium sulphate+ Water+ Ammonia.
q) Nitric acid+ Magnesium carbonate --> Magnesium nitrate+ Water+ Carbon dioxide.
r) Iron [III] oxide+ Sulphuric acid --> Iron [III] sulphate+ Water.
s) Zinc sulphide+ Oxygen --> Zinc oxide+ Sulphur dioxide.
t) Carbon+ Nitric acid --> Carbon dioxide+ Water+ Nitrogen dioxide.
7) Match the different types of chemical reactions in column II with the meaning of the type of reactions in column I.
COLUMN I
a) A chemical reaction in which two or more elements or compounds react to form one new compound as a product.
b) A chemical reaction in which a chemical compound decomposes or splits up into two or more simpler substances. It is generally brought about by heat.
c) A chemical reaction which takes place when an element [or radical] has replaced another element in a compound.
d) A chemical reaction in which two reactants are both the decomposed to form new substances by exchanging their radicals.
e) A chemical reaction which employes a catalyst to alter the rate of a reaction.
f) A chemical reaction in which the products formed react together to form the original reactants depending on the conditions of the reaction.
g) A reaction in which a substance dissociates into two or more simpler substances on application of heat and is a reversible reaction.
h) A reaction which involves addition of oxygen or electronegative element or removal of hydrogen or electropositive element.
i) A reaction which involves addition of hydrogen or electropositive elements or removal of oxygen or electronegative element.
j) A chemical reaction which proceeds with evolution of heat energy.
k) A chemical reaction which proceeds with absorption of heat energy.
l) A chemical reaction which proceeds with absorption of light energy.
COLUMN II
A) Double decomposition
B) Exothermic reaction
C) Reversible reaction
D) Displacement reaction
E) Combination or synthesis
F) Decomposition reaction
G) Thermal dissociation
H) Endothermic reaction
I) Catalytic reaction
J) Oxidation reaction
K) Photochemical reaction
L) Reduction reaction.
8) With reference to the reaction -- A to L in column II of the previous question no. 7 state the type of reaction/s to which each of the following belongs :
a) Addition of zinc to copper sulphate solution.
b) Heat on lead nitrate crystals.
c) Preparation of oxygen from potassium chlorate.
d) Conversion of ferrous chloride to ferric chloride using chlorine.
e) Formation of ammonia from nitrogen and hydrogen.
f) Liberation of hydrogen at the cathode acidified water.
g) Manufacture of glucose by green plants.
h) Formation of nitric oxide from Nitrogen and oxygen.
i) Addition of zinc to dilute sulphuric acid.
j) NH₄Cl <=> NH₃ + HCl.
k) 2KNO₃ --∆--> 2KNO₂ + O₂.
l) 2H₂O₂ --H₃PO₄--> 2H₂O + O₂.
m) PbBr₂ --> Pb²⁺ + 2Br¹⁻ [ions].
n) 2HgO --∆--> 2Hg + O₂.
o) N₂O₄ <=∆=> 2NO₂.
p) AgNO₃ + KCl --> AgCl + KNO₃.
q) Fe + S --> FeS.
r) H₂ + Cl₂ --> 2HCl.
ˢᵘⁿˡᶦᵍʰᵗ
s) C + H₂O --> CO.
t) Cl₂ + 2KI --> 2KCl + I₂.
u) 3Fe + 4H₂O <==∆=> Fe₃O₄ + 4H₂.
v) 2Cu + O₂ --> 2CuO.
w) Fe₂O₃ + 2Al --> Al₂O₃ + 2Fe.
x) KNO₃ + H₂SO₄ --> HNO₃ + KHSO₄.
y) 2FeCl₂ + Cl₂ --> 2FeCl₃.
z) Fe+ H₂SO₄ --> FeSO₄ + H₂.
a) SO₂ + Cl₂ --> SO₂Cl₂.
b) 3Ca + N₂ --> Ca₃N₂.
c) CuSO₄ + Fe --> FeSO₄ + Cu.
d) 4HNO₃ --> 2H₂O + 4NO₂ + O₂.
8) Oxidation and reduction reactions are generally termed as redox reactions . In the examples given below underline the oxidised product or reduced product in the respective reactions. Underline substance is the oxidising or reducing agent respectively.
Oxidation reactions
a) Cu + O₂ --> 2CuO.
b) H₂S + Cl₂ --> S + 2HCl.
c) 2FeCl₂ Cl₂ --> 2FeCl₃.
d) SO₂ + H₂O + Cl₂ --> H₂SO₄ + 2HCl.
e) H₂S + 2FeCl₃ ---> 2FeCl₂ + 2HCl + S.
f) Zn + H₂SO₄ --> ZnSO₄ + H₂.
g) Fe + S --> FeS.
h) 2Mg + SO₂ --> MgO + S.
i) 2H₂S + SO₂ --> 3S + 2H₂O.
j) S + 2H₂SO₄ ---> 3SO₂ + 2H₂O.
Reduction reactions
a) CuO + H₂ --> Cu + H₂O.
b) Br₂ + H₂S --> 2HBr + S.
c) 2FeCl₃ + H₂S --> 2FeCl₂ + 2HCl + S.
d) 2HgCl₂ + SnCl₂ --> Hg₂Cl₂ + SnCl₄.
e) 2FeCl₃ + SO₂ + 3H₂O --> 2FeCl₂ + 2HCl + H₂SO₄.
f) Fe₂(SO₄)₃ + 2H₂O + SO₂ --> 2FeSO₄ + 2H₂SO₄.
g) Cl₂ + 2H₂O + SO₂ --> 2HCl + H₂SO₄.
h) 2HNO₃ + SO₂ --> 2NO₂ + H₂SO₄.
i) 2KMnO₄ + 2H₂O + 5SO₂ --> 2MnSO₄ + K₂SO₄ + 2H₂SO₄.
j) K₂Cr₂O₇ + H₂SO₄ + 3SO₂ --> Cr₂(SO₄)₃+ K₂SO₄ + H₂O.
9) Name the following:
a) A coloured gaseous oxidising agent.
b) A liquid oxidising agent which on thermal decomposition in presence of a catalyst liberates oxygen.
c) A gaseous reducing agent containing Oxygen.
d) An acidic other than nitric and Sulphuric Acid which is an oxidizing agent.
e) A gaseous reducing agent neutral in nature other than carbon monoxide.
f) An oxidizing agent which liberates chlorine on heating with concentric hydrochloric acid.
g) Two neutral gases which react to give a basic gas and the reaction is exothermic.
h) Two neutral gases which react to give a neutral oxide and the reaction is exothermic.
i) A substance which decomposes by absorption of sound energy.
j) Two substances which react explosively on close physical contact.
ATOMIC STRUCTURE
1) Define the terms
a) Atomic number
b) Mass number
c) Electron
2) From the symbol ⁴₂He for the elements helium, write down the mass number and the atomic number of the element.
3) a) Sulphur as an atomic number of 16 and a mass number of 31. State the number of protons and neutrons present in the nucleus of sulphur.
b) Give a simple diagram to show the electrons in an atom of sulphur.
4) ²⁴₁₂Mg and ²⁶₁₂ Mg are symbols of two isotopes and magnesium. compare the atoms of these isotopes with respect to:
a) the composition of their nuclei.
b) their electronic configurations .
c) give the reason why the two isotopes of magnesium have different mass numbers.
5) Chlorine is an element of atomic number 17. It is a mixture of two Isotopes having mass number of 35 and 37.
a) What is meant by "atomic number of an element"? What do you understand by an 'atom'.
b) Write down the electronic configuration the chlorine atom.
c) State the number of protons , electrons and a neutrons in the following isotopes: ³⁷Cl₁₇, ³⁷Cl₁₇.
d) Explain why the two atoms in (c) above have the same chemical reactions.
e) If molten magnesium chloride is electrolysed suggest suitable electrode(anode). Carbon
6) Five atoms are labelled V to Z
Atoms mass number. Atomic number
V 40 20
W 19 9
X 7 3
Y 16 8
Z 14 7
i) Which one of these atoms (a) contains 7 protons (b) has an electronic configuration 2.7 ? Z, W
ii) Write down the formula of the compound formed by atoms X and Y. X₂Y
7) Element X, Y, Z have atomic numbers 6, 9 and 12 respectively, Which one:
a) forms anions - negative ion.
b) forms cation - positive ion.
c) has 4 electrons in the outermost orbit.
8) The atoms of aluminium is represented by ²⁷Al₁₃. Write down the number of
a( electrons
b) protons
c( neutrons
d) the arrangement of electrons in the different orbits or shells in one atom of aluminium.
9) Name the element which does not contain any neutrons in its nucleus.
10) Elements A, B, C have atomic number 9, 20 and 10 respectively.
a) State which one is (i) a nonmetal (b) a metal (c) a chemically insert
b) Write down the formula of the compound formed by two of the above elements.
11) Write down the electronic configuration of the following:
a) ²⁷₁₃X
b) ³⁵₁₇Y.
Write down the number of electrons in X and neutrons in Y and the formula of the compound formed by X and Y. XY₃
12) Write down:
a) The mass number of the atom having 20 neutrons and 15 protons.
b) The number of neutrons in the nucleus of an atom having atomic number 17 and mass number 37.
13) What is the relation between the number of protons and the number of electrons in an atom.
14) Copy and complete the following table relating to the atomic structure of some elements.
Element At. No Mass.no pro neu elect
Beryllium 4. 9
Fluorine 9 10
Sodium 12 11
Phosphate. 31 15
15) The electronic structure (configuration) of fluorine can be written as 2,7. In a similar way give the electronic configuration of:
a) aluminium
b) phosphorus
16) Represent each of the following:
a) a proton 'p'.
b) an electron 'e'.
c) a neutron 'n' in terms of its symbols showing the subscript and superscript values.
17) An element 'A' has mass number 23 and atomic number 11. State the
a) number of neutrons in its shell.
b) electronic configuration of the element 'A'.
18) The following elements U and Z are given :
₃U, ₆V, ₉W, ₁₄X, ₁₈Y, ₂₀Z.
State the electronic configuration of each and state whether they are metals, non metals or insert gases.
19) Draw the geometrical atomic structure of each of the following atoms showing the number of electrons, protons and neutrons in each of them:
a) ¹²₆C
b) ²³₁₁Na
c) ³¹₁₅P
d) ³⁹₁₉K
e) ⁴⁰₂₀Ca
20) Four elements A, B, C, D are given :
A shows the presence of 20 neutrons and 17 electrons.
B shows the presence of 18 neutrons, 17 protons and 17 electrons.
C shows the presence of 10 neutrons, 9 protons and 10 electrons.
D shows the presence of 4 neutrons , 3 protons and 1 electrons.
State which of the above is-
a) an atom
b) a cation
c) a pair of isotopes.
Write the formula of the compound formed between D and C.
21) Difference between the terms -
a) stable and unstable electronic configuration
b) Duplet and octet rule
c) Electron and proton
d) atomic number and mass number
e) nucleus and nucleons
f) Valence shell and penultimate shell
22) Select the correct answer from the answers in brackets to complete each sentence.
a) An element has electronic configuration 2, 8, 1 and 12 neutrons. Its mass number is ____( 11/23 /12).
b) The maximum number of electrons in M shell is _____(8/32/18).
c) Isotopes have same____( number of neutrons/ electronic configuration/ atomic masses).
d) An___( atom/ion) is capable of independence existence in solution.
e) An atom with electronic configuration 2,7 and mass number 19 will have____ (8/10/12).
23) Give reasons for the following:
a) the physical properties of isotopes of the same element are not identical.
b) the mass number of an atom is slightly less than the actual atomic mass.
c) the shells surrounding the nucleus of an atom are also called 'energy levels'.
d) Helium is chemically extremely unreactive.
e) Mass number is slightly less than the actual atomic mass.
24) Name the state the following:
a) the three isotopes of hydrogen.
b) Two elements having same number of protons and electrons but different number of neutrons.
c) the valency of an element whose electronic configuration is 2, 8, 3.
d) the shell closest to the nucleus of an atom.
e) An element having valency zero.
25)
State the number of neutrons in each of the atoms A to E. Also state which of the atoms A to E is a metal.
26) Match the elements A to E in list 1 with their valencies in list 2 and with their nature in list 3.
List : 1
A) Atomic number 7, mass number 14
B) Electronic configuration 2,8.
C) neutrons 14, electrons 13
D) neutrons 22, protons 18.
E) electronic configuration 2,8,1
List: 2
1) -3
2) +1
3) +3
4) +2
5) 0
List: 3
X: metal
Y: nonmetal
Z: noble gas
