School of elements.
1.
Which scientist stated the “Law of
Triad”? (Dobereiner)
2.
Who introduced the “Law of Octaves”?
(Newlands)
3.
What was Mendeleev’s basis for the
classification of elements? (atomic mass)
4.
The unknown element of Mendeleev’s
periodic table, Eka – Aluminium was later named as (gallium)
5.
How many elements are there in the 4th and 5th period of modern periodic table? (18)
6.
Halogens belongs to which group in
Modern Periodic Table? (seventeenth)
7.
Which is the longest period in Modern
Periodic table? (sixth)
8.
What is the valency of first group
elements? (one)
9.
Transition elements belong to which
block in modern periodic table? (d)
10.
Zero group elements exist in which
physical state at ordinary temperature? (gaseous)
11.
Which element has electronic
configuration 2,8,2? (Mg)
12.
The electronic configuration of element
‘y’ is 2,7. What is its valency?(one)
13.
What happens to atomic size of elements
on moving from left to right in a period?(decreases)
14.
What are normal elements? (s and p block
elements)
15.
The element x belongs to group five.
What is the number of valence electrons in x? (five)
16.
In which period the element ‘x’ belongs,
if its electronic configuration is 2, 8, 1? (third)
17.
What is the valency of the element with
atomic number 17? (one)
18.
Which block elements have last three
shells incompletely filled? (f)
19.
Sulphur, carbon, iodine belongs to which
block in Modern periodic table? (p)
20.
Which element has twice as many
electrons in its second shell as its first shell? (carbon)
21.
A, B and C are the elements of
Doberener’s triad. If the atomic mass of A is 40 and that of C is 137. What
would be the atomic mass of B? (88.5)
22.
The element A belongs to which group it
is atomic number if 23? (fifth group)
The Magic of Chemical Reactions
1.
What happens when silver chloride is
exposed to sunlight?(silver metal is formed)
2.
What is the chemical formula of Plaster
of Paris (POP)? (CaSO4. H2O)
3.
What happens during reduction reaction?
(reactants gain hydrogen)
4.
What is called the addition of oxygen to
a substance? (oxidation reaction)
5.
What is the odour of H2S gas?
(rotten egg)
6.
What type of chemical reaction take
place when magnesium wire is burnt in air? (combination reaction)
7.
What type of chemical reaction takes
place when lime stone is heated? (decomposition reaction)
8.
How are food products containing fats
and oils are packaged in order to prevent from spoilage? (nitrogen)
9.
When soap is scrubbed on a white cloth,
where a yellow stain of curry is present, it changes into reddish brown. This
is due to: (neutralization reaction)
10.
Silver ornaments become dark on
prolonged exposure to air. This is due to the formation of layer of its.
(sulphide)
The acid base chemistry
1.
The colour of universal indicator
solution is: (greenish yellow)
2.
The substance which is bitter to taste
is: (an alkali)
3.
A student measured the PH values of four
solutions marked A, B, C and D found them to be 6, 12, 2 and 14 respectively.
The solution which is likely to be strongly acidic is: (C)
4.
What is the pH value of neutral
solution? (7)
5.
What colour change takes place when
phenolphthalein is added to NaOH solution? (pink)
6.
What is the taste of acidic substances?
(sour)
7.
Acids turn blue litmus into: (red)
8.
What is litmus paper? (natural indicator)
9.
What do all acids contain? (hydrogen)
10.
Give the chemical formula for baking
soda. (NaHCO3)
11.
What is the common name for sodium
hydrogen carbonate? (Baking soda)
12.
Which salt is used to disinfect water?
(bleaching power)
13.
A solution in test tube A has pH less
than seven, which kind of solution it is? (acidic)
14.
Which colour does the methyl orange
indicator give in basic solution?(yellow colour)
15.
Name the plant from which Litmus solution
is extracted. (Lichen)
16.
Which salt is used to reduce acidity in
stomach? (baking soda)
17.
Which salt is used in manufacturing
paper? (sodium carbonate)
18.
Name the salt which makes hard water
soft? (Na2CO3)
19.
Which salt is used in fire extinguisher?
(NaHCO3)
20.
The carboxylic acid present in milk is:
(Lactic acid)
21.
What is milk of magnesia? (magnesium
hydroxide)
The electric spark
1.
When current is plotted against
potential difference, a straight line plot is obtained, which of the following
law is verified? (Ohm’s law)
2.
When the resistance of the conductor
increases then the current will: (decrease)
3.
Keeping the potential difference
constant the resistance of the circuit is made four times. How much does the
current change? (becomes one fourth)
4.
If the resistance is to be increased
then the number of resistances should be connected in: (series)
5.
What is the equivalent resistance of
three resistances of 2 ohms, 3 ohms and 4 ohms are connected in series? (9 ohms)
6.
In series combination which remains
constant? (current)
7.
You are given three equal resistances,
in how many combinations can they be arranged? (four)
8.
Which instrument is used to measure
electric current? (ammeter)
9.
Which instrument is used to measure
potential difference? (voltmeter)
10.
Which physical quantity has the unit
ohm? (resistance)
11.
Which combination is used to decrease
resistance in the circuit? (Parallel)
12.
How would the three resistance of 3 ohms
each be connected so as to produce an equivalent resistance of 1 ohm. (all in
parallel)
13.
If we want to connect a large number of
electric bulbs for decorating buildings which circuit is better? (series)
14.
Keeping the potential difference
constant, the resistance of the circuit is doubled. By how much does the
current change? (half)
15.
Which particles constitute the electric
current in a metallic conductor? (electrons)
16.
What is the SI unit of electric charge?
(coulomb)
17.
What is the SI unit of electric current?
(Ampere)
18.
Who invented battery? (Alessandro Volta)
19.
Which metal has lowest resistivity?
(silver)
20.
What is the commercial unit of
electrical energy? (kilowatt – hour)
21.
By what other name is the unit Joules /
Coulomb called? (volt)
22.
What is the SI unit of resistivity? (ohm
– metre)
23.
Which of the following is a best
conductor of electricity? (silver)
24.
Which is the allow of Cu and Ni?
(constantan)
25.
Which material is used to make filament
of an electric bulb? (tungsten)
26.
Which device work on the principle of
heating effect of electric current. (fuse)
27.
Which substance has infinitely high
resistance? (rubber)
28.
What is the resistivity of silver? (1.60
x 10 – 8 ohm m)
29.
How is electric power calculated?
(electric power = potential
difference x current)
30.
What material is used in electric iron
as a heating element? (nichrome)
