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PERIODIC CLASSIFICATION OF ELEMENTS

 


HOTS
1.   On what basis did Mendeleev classified the element?
2.   Define ‘groups and period’?
3.   What is common among all the elements present in one period?
4.   Name two alkali metals present in Group 1.
5.   An element X belongs to II group and 2nd period. Write atomic number and name of element.
6.   The electronic configuration of an atom is 2,8,7. Give its atomic number, nature of oxide.
7.   Why are noble gases placed in a separate group?
8.   Lithium, sodium potassium belong to same group called alkali metals. Wjy?
9.   Give characteristics of period.
10.   State three points of difference between Mendeleev’s Periodic Table and Modern Periodic Table.
1.   How many groups and periods are there in the modern periodic table? How do the atomic size and metallic character of elements vary as we move:
       (a) down a group and
       (b) from left to right in a period (CBSE 2015)
2.   How many vertical columns are there in the modern periodic table and what are they called? (CBSE 2013)
3.   Given below are some elements of the modern periodic table:
            4Be, 9Fe,14Si, 19K, 20Ca
            (i)Select the element that has one electron in the outermost shell and write its electronic configuration.
            (ii)Select two elements that belong to the same group. Give reason for you answer.
            (iii)Select two elements that belong to the same period. Which one of the two has bigger atomic size? (CBSE 2013)
4.   Write the number of periods the modern periodic table has. How do the valency and metallic character of elements vary on moving from left to right in a period? How do the valency and atomic size of elements vary down a group? (CBSE 2013)
5.   An element �M� has atomic number 12.
6.   (a)Write its electronic configuration.
        (b)State the group to which �M� belongs.
        (c)Is �M� a metal or a non-metal.
        (d)Write the formula of its chloride. (CBSE 2012)
7.   What physical and chemical properties of elements were used by Mendeleev in creating his Periodic Table? List two observations which posed a challenge to Mendeleev�s Periodic Law. (CBSE 2008 F)
8.   State any two limitations to Mendeleev�s classification.
            How does electronic configuration of atoms change in period with increase in atomic number?
            (CBSE 2009)
9.   (i) How do you calculate the possible valency of an element from the electronic configuration of its atoms?
            (ii) Calculate the valency of element X whose atomic number is 9 (CBSE 2011)
10.   On the basis of electronic configuration, how will you identify the first and the last element of a period? (CBSE 2011)
MULTIPLE CHOICE QUESTIONS
1.   14 elements after actinium is called
        a. Lanthanides
        b. Actinides
        c. D-block elements
        d. P block elements
2.   An element has an atomic number of 15 with which of the following elements will it show similar chemical properties.
        a. Be (4)
        b. Ne (10)
        c. N(7)
        d. O (8)
3.   The group number and period number respectively of an element with atomic number 8 is.
        a. 6,2
        b. 16,2
        c. 6,8
        d. 16,4
4.   An element belongs to period 2 and group 2 th number of valence electrons in the atoms of this element is.
        a. 2
        b. 4
        c. 3
        d. 1
5.   In the third period of the periodic table the element having smallest size is
        a. Na
        b. Ar
        c. Cl
        d. Si
6.   Electronic configuration of Al+3 is
        a. 2,8,3
        b. 2,8,8
        c. 2,8
        d. 2,8,8,3
7.   Identify the group which is not a Dobereiner triad
        a. Li, Na, K
        b. Be, Mg, Cr
        c. Ca, Sr, Ba
        d. Cl, Br, I
8.   Which is not true about the noble gases?
        a. They are non metallic in nature
        b. They exist in atomic form
        c. They are radioactive in nature
        d. Xenon is the most reactive among these
9.   Identify the wrong sequence of the elements in a group
        a. Ca, Br, Ba
        b. Cu, Au, Ag
        c. N,P, As
        d. Cl, Br, I
10.   An element with atomic number will form a basic oxide________
        a. 7
        b. 17
        c. 14
        d. 11
ANSWERS
1.    B
2.    C
3.    A
4.    A
5.    B
6.    C
7.    B
8.    C
9.    B
10. D

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