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
