Periodic classification of elements

At the time of Mendeleev, the number of elements known was

• (a) 63

• (b) 65

• (c) 62

• (d) 64

The properties of eka-aluminium predicted by Mendeleev are the same as the properties of later discovered element

• (a) Scandium

• (b) Germanium

• (c) Gallium

• (d) Aluminium

An atom of an element has the electronic confi-guration 2,8,2. To which group does it belong?

• (a) 4th group

• (b) 6th group

• (c) 3rd group

• (d) 2nd group

The arrangement of elements in the Modem Periodic Table is based on their

• (a) increasing atomic mass in the period

• (b) increasing atomic number in the horizontal rows

• (c) increasing atomic number in the vertical columns

• (d) increasing atomic mass in the group

Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table?

• (a) Group 8

• (b) Group 2

• (c) Group 18

• (d) Group 10

Element ‘X’ forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:

• (a) Si

• (b) Mg

• (c) Al

• (d) Na

Pick out the chemically most reactive elements from the given triads.Li, Na, K F, Cl, Br

• (a) Li and F

• (b) Li and Br

• (c) K and F

• (d) K and Br

A metal ‘M’ is in the first group of the Periodic Table. What will be the formula of its oxide?

• (a) MO

• (b) M₂O

• (C) M₂O₃

• (d) MO₂

Name the neutral atom in the Periodic Table which has the same number of electrons as K+ and Cl-.

• (a) Helium

• (b) Argon

• (c) Neon

• (d) Krypton

An element ‘A’ belongs to the third period and group 16 of the Periodic Table. Find out the valency of A.

• (a) Valency = 6

• (b) Valency = 2

• (c) Valency = 1

• (d) Valency = 3