Q. Atoms of eight elements A. B. C. D, E, F. G and H have the same number of electronic shells but different number of electrons in their outermost shell. It was found that elements A and G combine to form an ionic compound. This compound is added in a small amount to almost all vegetable dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are acidic. The oxide of D is almost neural. Based on the above information answer the following questions:
(i) To which group or period of the periodic table do the listed elements belong?
(ii) What would be the nature of compound formed by a combination of elements B and F?
(iii) Which two of these elements could definitely be metals?
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(v) If the number of electrons in the outermost shell of elements C and G are 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Answers
(A in grp. 1, B in 2, C in 13, D in 14, .... H in 18)
2) ionic compound as one is metallic (B) and the other nonmetallic (F)
this is because B's oxide is basic like metallic oxides and F's is acidic like nonmetallic oxides.
3) A and B as their oxides are metallic.
4) H as it belongs to 18th group which includes noble gases. thus H is most likely to be gaseous.
5) CG3.
C's valency is 3 and G's is 1, therefore by cross multiplication method it can be seen to be C1G3, or CG3.
[A is Na/sodium, B is Mg/magnesium, C is Al/aluminium, D is Si/silicon, E is P/phosphorus, F is S/sulphur, G is Cl/chlorine, H is Ar/argon
Answer:
Given:
All elements A, B, C, D, E, F, G and H have same number of electronic shell.
A and G combine to form an ionic compound.
Compound formed, is added in a small amount to almost all vegetable dishes during cooking.
Oxides of elements A and B are basic in nature.
Oxides of E and F are acidic.
The oxide of D is almost neural.
(i) To which group or period of the periodic table do the listed elements belong?
All the elements belong to 3rd period.
Groups of elements are 1, 2, 13, 14, 15, 16, 17, 18 resp.
(ii) What would be the nature of compound formed by a combination of elements B and F?
Since B is mwtallic and F is non-metallic, they will form ionic compounds.
(iii) Which two of these elements could definitely be metals?
Since oxides of A and B are basic in nature, these elements are metals.
(iv) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
Last element, i.e H belongs to noble gases (18th group), thus it can be found in gaseous state at room temperature.
(v) If the number of electrons in the outermost shell of elements C and G are 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Since valency of C is 3 and that of G is 7, C will donate 3 electrons while G will gain 1 electron. Thus the compound formed is: .