1. Which of the following statements is not a correct statement about the trends when
going from left to right across the periods of periodic Table.
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
2. Element X forms a chloride with the formula XCl2, 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) AI (d) Si
3. Which element has
(a) two shells, 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 valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?
4. (a) What property do all elements in the same column of the Periodic Table as
boron have in common?
(b) What property do all elements in the same column of the Periodic Table as
fluorine have in common?
5. 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)
6. The position of three elements A, B and C in the Periodic Table are shown below –
Group 16 Group 17
- -
- A
- -
B C
7. 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?
8. How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
9. In the Modern Periodic Table, calcium (atomic number 20) is surrounded by
elements with atomic numbers 12, 19, 21 and 38. Which of these have physical
and chemical properties resembling calcium?
10. Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.