Why halogens are coloured?

Most of the halogens are coloured because they absorb radiations which are in the visible region which in turn excite the valence electrons to higher energy levels. As the amount of energy which is required to excite the electrons to a higher level is different for different halogens, each halogen has a different colour.

Fluorine exhibits only one oxidation state - 1 whereas other halogens show variable oxidation states. Why?

Fluorine is the most electronegative element in the periodic table and cannot exhibit any positive oxidation state as it does not have d orbitals in its valence shell for the excitation of electrons. Other halogens have d − o r b i t a l s and therefore, can expand their octets and show + 1 , + 3 , + 5 , + 7 oxidation states also.

Write formula and structure of three oxoacids of sulphur.

Oxoacids are acids that contain oxygen. In oxoacids of sulphur, sulphur exhibits a tetrahedral structure. Generally, oxoacids of sulphur contain at least one S = O bond and one S - OH bond. Some popular oxoacids of sulphur are (i) Sulphuric acid: The chemical formula of sulphuric acid is H 2 SO 4 . The structure of sulphuric acid is: (ii) Sulphurous acid: The chemical formula of sulphurous acid is H 2 SO 3 . The structure of sulphurous acid is: (iii) Peroxodisulphuric acid: The chemical formula of peroxodisulphuric acid is H 2 S 2 O 8 . The structure of the compound is

Ionization energy of noble gases is very high. Why?

Ionization energy is defined as the energy required to remove an electron from the valence shell of an atom. Since noble gases have completely filled valence shells that are highly stable, a lot of energy would be required to remove even a single electron from the valence shell of a noble gas. This is the reason why noble gases usually have very large ionization energies.

Explain the following property of elements of 17th group : Electronegativity

The elements of halogen family have high value of electronegativity. Fluorine is the most electronegative element in the periodic table. The value decreases as we move down the group from fluorine to iodine indicating a gradual decline in the non-metallic character. This decrease is attributed to the increase in atomic radius and hence less attraction between the positively charged nucleus and the electrons. Decrease order of electronegativity is, F > Cl > Br > I .

Explain the following property of elements of 17th group : Oxidation state

The electronic configuration of valence shell of each element of group is ns 2 np x 2 np y 2 np z 1 . There are 7 electron in the valence shell. Therefore, an atom of halogen can attain a stable electronic configuration by gaining one electron from some electropositive element and show oxidation state -1. They can also share an electron pair with another atom of its own type or some other atom to form covalent bond and show a covalency of 1. Therefore, all the halogens exhibit an oxidation state of -1 or covalency of 1. Because of the presence of vacant d -orbitals in the valence shell, the halogen atoms (except fluorine) can expand their oxidation number and thus can have higher positive oxidation states. This happens in their oxides and inter halogen compounds.

Ozone is a strong oxidizing agent. Explain with chemical equation.

Ozone is a strong oxidising agent because it readily undergoes decomposition to produce atomic oxygen. O 3 → O 2 + O Ozone reacts with all the metals except gold and platinum producing oxides. It oxidises mercury and forms mercurous oxide. Mercury loses its mobility due to the formation of mercurous oxide which sticks to the glass. 2 Hg + O 3 → Hg 2 O + O 2 Ozone oxidises silver to silver oxide by reducing itself. 2 Ag + O 3 → Ag 2 O + O 2

Describe Siemens ozonier method of preparation of ozone under the following points: (i) Theory and equations (ii) Labelled diagream

Ozone is obtained when silent electric discharge is passed through pure, cold and dry dioxygen in a specially designed apparatus called ozoniser. The types are Siemens' ozoniser and Brodie's ozoniser. The equation for the chemical reaction is: 3 O 2 ⇄ silent electric discharge 2 O 3 It consists of two co-axial glass tubes fused together. Tin foil is used to coat the inner-side of the inner tube and the outer-side of the outer tube. The inner and outer tin coatings are connected to the terminals of an induction coil, which produces current of high voltage. A slow current of pure and dry oxygen is passed through the annular space. On subjecting oxygen to silent electrical discharge, ozonised oxygen containing 10 - 15 % of ozone is formed. By taking the following precautions, the yield of ozone can be increased in the ozonised oxygen: (i) Only pure and dry oxygen should be used . (ii) The ozoniser should be perfectly dry . (iii) Low temperature should be maintained and there should be no sparking. When a silent electric discharge is passed through pure, cold and dry dioxygen taken is Siemen’s ozonizerRead more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products When a silent electric discharge is passed through pure, cold and dry dioxygen taken is Siemen’s ozonizerRead more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products When a silent electric discharge is passed through pure, cold and dry dioxygen taken is Siemen’s ozonizerRead more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products When a silent electric discharge is passed through pure, cold and dry dioxygen taken is Siemen’s ozonizerRead more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products When a silent electric discharge is passed through pure, cold and dry dioxygen taken is Siemen’s ozonizerRead more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products Read more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products Read more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products Read more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products Read more on Sarthaks.com - https://www.sarthaks.com/831835/how-can-ozone-be-manufactured-siemens-ozonizer-how-pure-ozone-recovered-from-the-products

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - The p-Block Elements>Chattisgarh Board-2018>Q 3

EASY

12th Chhattisgarh Board

IMPORTANT

Earn 100

What is the difference between $α$ — particle and $He$ atom?

Chapter-Wise 3D Chemistry Videos from Embibe Experts EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY

07 min 44 sec

Anomalous Properties of Fluorine

Anomalous properties of fluorine may be attributed due to its very small size, high electronegativity and absence of vacant d-orbitals in the valence shell....

05 min 55 sec

Chemical Properties of Halogens

The halogens are known as reactive elements due to their high electronegativity, which is due to their highly effective nuclear charge. Learn about the react...

06 min 22 sec

Properties of Group 17 Elements

The Group 17 elements are known to be highly reactive elements. They form halides with most of the metals and non-metals. Let’s explore a few of these proper...