Question

Homework 7: 211 CHM-2017-2018 Answer the following question: 1. Mark the following sentences with (V) or (x) 1. Ionisation enthalpy of Group16 decreases down the group and have lower values compared to those of Group 15 in the corresponding periods() 2 Oxygen and sulphur are metals, selenium and tellurium metalloids, whereas polonium is a non-metal() 3. All of Group 16 elements exhibit allotropy ( ) 4. Bonding in +4 and +6 oxidation states of Group16 elements are ionic ) 5. The stability of +6 oxidation state of Group16 elements increases down the group () 6. Stability of + 4 oxidation state of Group 16 elements increase inert pair effect) 7. 8. Sulphur, selenium and tellurium usually show + 4 oxidation state in their compounds with oxygen and + 6 with fluorine ) Since electronegativity of oxygen is very high, it shows only negative oxidation state as -2 except in the case of OF 2 where its oxidation state is +2( )The stability of -2 oxidation state of Group 16 elements increases down the group 9. Polonium hardly shows - 2 oxidation state() 10. Their acidic character decreases from H2O to Hate() 11. The thermal stability of hydrides of Group 16 elements increases from H20 to HaPO() 12. All the hydrides of Group 16 elements except water possess reducing property and this character increases from HS to HzTe() 13. All these elements of Group 16 form oxides of the EO2 and EOs types where EES, Se, Te or Po() 14. Os and SO2 are solid while SeO2 is gases ( ) 15. Reducing property of Group 16 dioxide decreases from SO2 to TeO2 ) 16. SO2 is reducing while TeO2 is an oxidising agent ) 17. The stability of Group 16 halides decreases in the order F C > Brno) 18. All elements of Group 16 except selenium form dichlorides and dibromides )

Answer 1

The solution of the first five questions are given below

1)ans True

reason - Ionisation enthalpy of group 16 elements decreases down the group and have and have lower values compared to that of group 15 elements corresponding elements because the ionisation enthalpy decreases down the group due to the increase in the size of the valence shell,also it is lesser than that of correspondig elements in group 15 because there are 5 electrons in the valence shell of group 15 elements whereas there is 6 electrons in the valence shell of group 16 elements.Thus there will be more electron-electron repulsion in group 16 elements than that of group 15 elements.

2)ans-True

The metallic effect of the elements decreases down the group and also decreases along the period.Oxygen and Sulphur are the first and second elements of group 16 whereas selinium and tellurium are the middle  elements hence they are metalloids and polonium is the lower element of the same group hence it is non-metal.

3)ans-True

All of the group 16 elements exhibit allotropy.

4)ans-True

The ionic bond is formed when there is large difference in the electronegitivity of the elements.Group 16 elements,thus oxygen and sulphur form ionic bond in +4 and +6 state

5)ans-True

The reason is that the higher oxidation states is preferable down the group.Mostly lower elements of the all groups are having higher oxidation states.

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