Q28 of 30 Page 196

In the following table, are given eight elements A, B, C, D, E, F, G and H (here letters are not the usual symbols of the elements) of the Modern Periodic Table with the atomic numbers of the elements in parenthesis.


(i) What is the electronic configuration of F?


(ii) What is the number of valence electrons in the atom of F?


(iii) What is the number of shells in the atom of F?


(iv) Write the size of the atoms of E, F, G and H in decreasing order.


(v) State whether F is a metal or a non-metal.


(vi) Out of the three elements B, E and F, which one has the biggest atomic size?

(i) Electronic configuration of F is

F12- 2, 8, 2


(ii) There are 2 valence electrons in the atom of F.


Explanation- Valence electrons are those electrons which present in the last shell.


(iii) There are 3 shells in the atom of F.


(iv) We know that atomic size increases from top to bottom in a group due to increment in shells. So the order will be H>G>F>E.


(v) Since F has 2 valence electrons so it will donate these two electrons to acquire noble gas electronic configuration. Hence it is a metal.


(vi) We know that atomic size increases from top to bottom in a group and decreases from left to right in a period. So B has the bigger atomic size.


More from this chapter

All 30 →
26

Atoms of seven elements A, B, C, D, E, F and g have a different number of electronic shells but have the same number of electrons in their outermost shells. The elements A and C combine with chlorine to form and acid and common salt respectively. The oxide of element A is liquid at room temperature and is a neutral substance, while the oxide of the remaining six elements are basic in nature. Based on the above information, answer the following question:

(i) What could the element A be?


(ii) Will element A to G belong to the same period or same group of the periodic table?


(iii) Write the formula of the compound formed by the reaction of the element A with oxygen.


(iv) Show the formation of the compound by a combination of element C with chlorine with the help of electronic structure.


(v) What would be the ratio of number of combining atoms in a compound formed by the combination of element A with carbon?


(vi) Which one of the given elements is likely to have the smallest atomic radius?

 27

In the following table, six elements A, B, C, D, E and F (here letters are not the usual symbols of the elements) of the modern Periodic Table with atomic numbers 3 to 18 are given:


(a) Which of these is (i) a noble gas, (ii) a halogen?


(b) If B combines with F, what would be the formula of the compound formed?


(c) Write the electronic configurations of C and E.

 29

(a) How does the atomic radius changes as you go

(i) from left to right in a period?


(ii) down a group in the periodic table?


(b) Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the Modern Periodic Table do these two elements belong? What type of bond will be formed between them and why?

 30

“The atomic number of Lithium is 3.” On the basis of this information answer the question that follows:

(a) Write the electronic configuration of Li


(b) To which group Li belong?


(c) Find valency of Li.


(d) Identify type of ion it will form.


(e) Write down the formula of the compound formed by it.