Q5 of 8 Page 25

The element Cu with atomic number 29 undergoes chemical reaction to form an ion with oxidation number +2.

a) Write down the subshell electronic configuration of this ion.


b) Can this element show variable valency? Why?


c) Write down the chemical formula of one compound formed when this element reacts with chlorine (17Cl).

a) Cu2+ = 1s2 2s2 2p6 3s2 3p6 3d9

b) Yes. Because in d-block elements there is very small energy difference between the outer most s subshell and the penultimate d subshell. Hence under suitable conditions, the electrons of d subshell also take part in chemical reactions. So, Cu shows variable valency.


c) CuCl2


Cu shows +2 oxidation state and Cl shows -1 oxidation states in the chemical reaction so when these two elements will react then the chemical formula will be CuCl2.


More from this chapter

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3

Pick out the wrong ones from the subshell electronic configurations given below.

a) 1s2 2s2 2p7


b) 1s2 2s2 2p2


c) 1s2 2s2 2p5 3s1


d) 1s2 2s2 2p6 3s2 3p6 3d2 4s1


e) 1s2 2s2 2p6 3s2 3p6 3d2 4s2

 4

The element X in group 17 has 3 shells. If so,

a) Write the subshell electronic configuration of the element.


b) Write the period number


c) What will be the chemical formula of the compound formed if the element X reacts with element Y of the third period which contains one electron in the p subshell?

 6

Certain subshells of an atom are given below. 2s, 2d, 3f, 3d, 5s, 3p

a) Which are the subshells that are not possible?


b) Give the reason.

 1

A part of the periodic table is given below. The symbols of elements given in the columns are not real.


a) Which are the elements having only one electron in the 4s subshell?


b) Which is the element in s block with the smallest atomic radius?


c) Which are the elements likely to form coloured compounds?


d) Which is the metal with the highest reactivity?


e) Which is the element with the least reactivity?


f) Which is the element in which the last electron is filled in the 4p sub shell? Find its atomic number.


g) Frame as many questions as possible to get each element in this table as the answer.