PERIODIC CLASSIFICATION
OF ELEMENTS
WORKSHEET
1.A substance “X” Which is an oxide of a group 2 element is used for
white washing. On treatment with water
it forms “Y” .The solution of “Y” turns red litmus blue.
(a)
Identify “X” and “Y”
(b)
Write the chemical equation
(c) Explain reason why red litmus changes to
blue.
2
(a)Which element was named as “Eka – Silicon” in Mendeleev’s periodic
table?
(b)Can the elements Na, Si and Cl classified
as Triads? Support reason
(c)
Arrange the following in decreasing order of metallic character. Support your
answer with reason
Na, N, Mg, F, O
3
(a)State reasons for the following:
(i)Both Mg and O have valency
equal to 2 .Are they chemically similar also?
(ii)Out of C,B and N elements , which has
the maximum size? Why?
(b)Find the period of the following elements having atomic number: 19and
9
4 Account for the following:
(a) Elements in a group of the periodic table have similar chemical
properties
(b) Discuss any two drawbacks of Mendeleev’s periodic table
5.(a)What property do all the elements in the same column of periodic
table as the Boron have in common?
(b)What property do all the elements in the same column of
oeriodic table as the Fluorine have in common?
6. (a) Lithium, sodium and potassium are all metals that react with water to
liberate hydrogen gas. Is there any similarity in the atoms of these elements?
(b) Helium is an
un-reactive gas and neon is a gas of extremely low reactivity. What, if
anything, do their atoms have in common?
7. By considering their position in the Periodic Table, which one of
the following elements would you expect to have maximum metallic
characteristic?
Ga, Ge, As, Se, Be
8 Name two elements you would expect to show
chemical reactions similar to magnesium. What is the basis for your choice?
9. Why do you think the noble gases
are placed in separate group?
10. Why do you think the noble gases
are placed in separate group?
11. An atom has electronic configuration 2, 8, 7.
(a) What is the atomic number of
this element?
(b)To which of the following
elements would it be chemically similar?
(Atomic numbers are given in
parentheses.)
N(7), F(9), P(15), Ar(18)
12. The position of three elements A, B and
C in the Periodic Table are shown below:
(a) State whether A is a metal or
non-metal.
(b) State whether C is more reactive
than A
(c) Will C be larger or smaller
in size than B?
(d) Which type of ion, cation or
anion, will be formed by element A?
13. Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong
to group 15 of the Periodic Table. Write the electronic configuration of these
two elements. Which of these will be more electronegative? Why?
14. Compare and contrast the arrangement of elements in Mendeleev’s Periodic
Table and the Modern Periodic Table
15. Element X forms a chloride with the formula 
which
is a solid with a high melting point. X would most likely be in the same group
of the Periodic Table as
which
is a solid with a high melting point. X would most likely be in the same group
of the Periodic Table as
(a) Na
(b) Mg
(c) Al
(d) Si
16. Which element has
(a) two cells, both of which are
completely filled with electrons?
(b) the electronic configuration
2, 8, 2?
(c) a total of three shells, with
four electrons in its valance shell?
(d) twice as many electrons in
its second shell as in its first shell?
17.How
many groups and periods are there in Modern periodic table? How do the atomic size and metallic character of
elements vary as we move
(a0 down
the group
(b)
across the period
18.(a)
From the elements select the element having one electron in the outermost shell
4Be, 9F19K,
20Ca
(b) two
elements of the same group
(c)Write
the formula and the nature of the compound formed by the union of 19K and
eleent X(2,8,7)
19.
Calcium is an element with atomic no 20.Statereason
(a) is
calcium metal or non metal?
(b)Wil
its atomic radius be larger or smaller than that of potassium with atomic
no.19?
(c) write
the formula of its oxide.
20. Two
elements P and Q belong to the same
period of the modern periodic table and are in group I and Group II respectively. Compare their following
characteristics in tabular form
(a) The
no of electrons in their atoms
(b) The sizes
of their atoms
(c) Their
metallic characters
(d) Their
tendencies to lose electrons
(e) the
formula of their oxides
(f) the
formula of their chlorides
21.
Taking the example of an element of atomic number 16, explain how the
electronic configuration of the atom of an element relates to the position in
modern periodic table and how valency of
an element is calculated on the basis of its atomic number.
22. An
element X (2,8,2) combines with NO3-, SO42-,
PO43- RADICALS. Write the formula of the three compounds
formed .To which group of the periodic table does the element X belong? Will it
form ionic or covalent compound,?
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