Q22 of 24 Page 5

In the following table,

The position of some elements A,B,C,D,E,F and G in the Modern Periodic Table is given as under:



a. In which group are inert elements placed?


b. What type of ions would B, C, E and F form?


c. Which elements would have chemical properties similar to C?


d. How many shells would A have?


e. What is the similarity between A and D?


f. Identify the most abundant element in the earth’s crust. (CBSE 2008)

(a) Inert elements are placed in group 18.


(b) Elements B and E are placed in group 16 that means these have 6 electrons in outermost shell and these elements require 2 electrons to acquire noble gas configuration. So elements B and E will form B2- and E2- type ions.


And elements C and F are placed in group 17 that means these have 7 electrons in outermost shell and these elements require only 1 electron to acquire noble gas configuration. So elements C and F will form C- and F- type ions.


(c) We know that elements with similar properties are placed in same group. So element F would have chemical properties similar to C.


(d) Since A is placed in 1st period so it has only one shell.


(e) A and D are placed in group 18 so these both elements have 8 electrons in outermost shell.


(f) Most abundant element in the earth’s crust is B because B is oxygen and oxygen is most abundant element in earth’s crust.

More from this chapter

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20

Define the following terms:(i) Valency; (ii) Atomic size(b) How do the valency and' the atomic size of the elements vary while going from left to right along a period in the modern periodic table? (CBSE 2014)

 21

The elements of a period of the periodic table are given in order from left to right with one of its element missing:

Na        Mg       Al       Si        S      Cl      Ar 

a. To which period do these elements belong?


b. One element of this period is missing. Which is the missing element and where should it be placed?


c. Which one of these elements in this period shows the property of catenation?


d. Which one of these elements is least reactive? (CBSE 2008)

 23

(i) The position of three elements A,B and C in the periodic table are shown below-


(a) State whether A,B and C is a metal or non-metal.


(b) State whether Cis more reactive or less reactive than A.


(c) Will B be larger or smaller in size than A .


(d) Which type of ion, cation or anion, will be formed by element A,B and C.


(e) Write the electronic configuration A, B and C. (CBSE 2010)

 24

a. The following is a list of the electron distributions of atoms of unknown elements.


Choose an element from the list for each of the following descriptions.


i. It is a noble gas.


ii. It is a soft metal with a low density.


iii. It has giant covalent structure similar to diamond.


iv. It can form a negative ion of the type X3-.


b. How does electronic configurations of atoms change in a period with increase in atomic number? (CBSE 2012)