CBSE Class 10 Science Worksheet
Unit I: Chemical Substances - Nature and Behaviour - Periodic classification of elements
1.
Fill in the blanks: The formula of chloride formed by the element A placed in group 14 is __________.
2.
Choose the correct answer: Among the elements Na, Rb, Cs, K which element has the highest atomic radius?
A)
Na
B)
Rb
C)
Cs
D)
K
3.
An element “X” has mass number 35 and the number of neutrons, is 18. Identify
the group number and period of “X"
A)
Grp-5, period-4
B)
Group - 8, period - 2
C)
Group- 18, period - 3
D)
Group 1, period 4
4.
Which element has two shells, both of which are completely filled with electrons?
A)
Helium
B)
Neon
C)
Oxygen
D)
Nitrogen
5.
Choose the correct answer: At the end of each period the valence shell is _______________.
A)
Partially filled
B)
Not filled
C)
Completely filled
D)
None of these
6.
Which of the following is not a metalloid?
A)
Ge
B)
Si
C)
Sb
D)
In
7.
Choose the correct answer: As we go across the period in a periodic table the valency _____________.
A)
Increases
B)
Decreases
C)
Remains same
D)
First increases then decreases
8.
On what basis did Mendeleev arrange the elements in his periodic table?
A)
atomic mass
B)
atomic number
9.
Choose the correct answer: The first alkali metal is ______________.
A)
Sodium
B)
Potassium
C)
Magnesium
D)
Lithium
10.
Which of the following is a Döbereiner's triad?
A)
Na,Ca,Mg
B)
Ca, Sr, Ba
C)
N,H,O
D)
Li, Ca, K
11.
State True or False: Properties of Lithium are similar to Sodium.
A)
TRUE
B)
FALSE
12.
Identify the position of element in the periodic table which is an inert gas with atomic number 2.
13.
Which of the following elements does not lose an electron easily?
A)
Na
B)
Ca
C)
Al
D)
Cl
14.
Which element has one electron in the outermost shell?
A)
Na
B)
Si
C)
Mg
D)
Cl
15.
which among the following will have highest hydration energy?
A)
CaCl2
B)
MgCl2
C)
SrCl2
D)
BaCl2
E)
RaCl2
16.
Choose the correct answer: Elements were arranged by Mendelev on the basis of _______________.
A)
Atomic number
B)
Atomic mass
C)
Electronic charge
D)
Both 1 and 2
17.
Which among the following elements have the largest atomic radii?
A)
Na
B)
Mg
C)
Al
D)
Si
18.
Write two shortcomings of Mendeleev’s periodic table.
19.
Choose the correct answer: Element R forms a chloride with the formula RCl2, which is a solid with a high melting point. R would most likely be in the same group of the Periodic Table as _________________.
A)
Na
B)
Mg
C)
Al
D)
Si
20.
Which one of the following elements exhibits the maximum number of valence electrons?
A)
K
B)
Ca
C)
Ge
D)
As
CBSE Class 10 Science Worksheet
Unit I: Chemical Substances - Nature and Behaviour - Periodic classification of elements
Answers
1.
ACl4
2.
Option C
3.
Option C
4.
Option B
5.
Option C
6.
Option D
7.
Option D
8.
Option A
9.
Option D
10.
Option B
11.
Option A
12.
Group 18 and Period 1
13.
Option D
14.
Option A
15.
Option B
Solution:
Hydration energy of M2+ions decreases with the increase in atomic radii .As down the group fromMg 2+ to Sr2+ the ionic radii increases with least value for Mg2+ .With smallest value for magnesium ion the hydration energy will have the highest value.
16.
Option B
17.
Option A
18.
(a) Unable justify the position of hydrogen is the periodic table (b) Unable to assign proper position to the different isotopes of the same
element
19.
Option B
20.
Option D
