1. The electronic configuration for them are ns²np⁶

• Helium 1s ²2s²
• Neon 1s²,2s²,2p⁶
• Argon 1s²,2s²,2p⁶,3s²,3p⁶
• krypton1s²,2s²,2p⁶,3s²,3p64s²3d¹⁰4p6
• xenon 1s²,2s²,2p⁶,3s²,3p64s²3d¹⁰4p⁶4d¹⁰5s²5p⁶
• radon 1s²,2s²,2p⁶,3s²,3p64s²3d¹⁰4p⁶4d¹⁰5s²5p⁶4f¹⁴5d¹⁰6s²6p⁶

ns² np⁶ except hellium i.e,( 1s²)..

The group 18 elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements are non-reactive and are called noble gases as they have their outermost orbit complete. Due to stable electronic configuration they hardly react with other elements.

Bcoz they do not react with any element..so,they r called as noble gases....and also bcoz of this reason they are also called as inert gases.

Helium Neon Argon Xenon Redon ??

Helium, Neon, Argon, Krypton , Xenon, Redon( redon is radioactive )...

Preparation of Bleaching Powder

Bleaching powder is synthesized by the action of chlorine gas (produced from the chlor-alkali process) on dry slaked lime (Ca(OH)₂).

Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O

Uses of Bleaching Powder

• It is used for bleaching dirty clothes in the laundry, as a bleaching agent for cotton and linen in the textile industry.
• It is a strong oxidizing agent, hence used as an oxidizer in many industries.
• It is used as a disinfectant which is used for disinfecting water to make potable water.

Dry slaked lime with reacts with chlorine to prepare bleaching powder.

Cl₂ ​+ Ca(OH)_2​​⟶CaOCl₂​+CaCl₂​+HCl

     Dry slaked lime

The mixture is known as bleaching powder.

Properties of Chlorine:

• It is a greenish yellow gas with pungent and suffocating odour.
• It is soluble in H₂O

The word “electrolysis” was introduced by Michael Faraday in the 19th century. In chemistry, electrolysis is a method that uses a DC to drive a non-spontaneous chemical reaction. This technique is commercially significant as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell.

The process by which ionic substances are decomposed into simpler substances when an electric current is passed through them.

Deacon's process is a process used for preparation of molecular chlorine.

It involves the use of hydrogen chloride and oxygen as reactants and copper chloride as catalyst at high temperatures.

In this process, hydrogen chloride gas is oxidized by atmospheric oxygen in the presence of  CuCl₂ as catalyst at 723 K.

The balanced reaction for deacon's process is written as :

4HCl + O₂ →2Cl₂ + 2 H₂O

 

The reason F-F bond is weak is that when a fluorine tries to combine with another fluorine atom through a covalent bond, even though it has a very high electronegativity, since fluorine atom has a very small radius the electrons in the atoms repel each other and make the bond weak.

Bcoz of size of fluorine.

1. Chlorine dioxide is used as oxidizer or disinfectant.

2. Chlorine dioxide is used for control of tastes and odors associated with algae and decaying vegetation.

3. For water treatment, chlorine dioxide has several advantages over chlorine and other disinfectants.

Bcoz it does not react with water. It remains as a dissolved gas in water. It selectively attacks the phenolic groups of lignin without degrading cellulose fiber, allowing for increased yield and higher strength bleached pump..

According to Ellingham diagram the lower the position of a metal line in the Ellingham diagram, the greater is the stability of its oxide i.e lower metal line will have most negative Gibbs free energy due to which metal will be most stable in the form of its oxide. Bromine being in between lacks both these characteristics. Thus, the stability of oxides of halogens decreases in the order : I > Cl > Br > F. Higher oxide halogens are more stable than the lower ones because the higher ones are less reactive than the lower ones and also the size of the atoms are more of higher so they are less reactive and hence the oxides are more stable.

Uses of Interhalogen Compounds

• These are used as non-aqueous solvents.
• They are used as a catalyst in few reactions.
• UF₆ which is used in the enrichment of ²³⁵ U is produced by using ClF₃ and BrF₃.

U (s) + 3ClF₃ (l) → UF₆ (g) + 3ClF (g)

• These are used as fluorinating compounds.

Interhalogen compounds r used as non-watery solvents. Also, we use these compounds as a catalyst in a number of reactions. We use UF6 in the enrichment of 235U. We can produce this by using ClF3 and BF3

While both Oxygen and Chlorine are chemically-active, they cannot form compounds with the inert gasses, while Fluorine is the most chemically-active of all the elements. Elements grouped together on the periodic table have similar electron configurations and therefore similar chemical properties and reactivity.

Oxygen fluorides are compounds of elements oxygen and fluorine with the general formula OnF2, where n = 1 to 6. Many different oxygen fluorides are known:

oxygen difluoride (OF2)
dioxygen difluoride (O2F2)
trioxygen difluoride or ozone difluoride (O3F2)[1][2]
tetraoxygen difluoride (O4F2)[3]
pentaoxygen difluoride (O5F2)
hexaoxygen difluoride (O6F2)[4]
dioxygen monofluoride(O2F)

tetraoxygen difluoride
Oxygen fluorides are strong oxidizing agents with high energy and can release their energy either instantaneously or at a controlled rate. Thus, these compounds attracted much attention as potential fuels in jet propulsion systems.

In oxides of halogen, the bonds are mainly covalent due to small difference in electronegativity between the halogens and oxygen: the bond polarity, however, increases as we move from F to I. The stability of oxides of iodine is greater than those of chlorine while bromine oxides are the least stable. For fluorine F this is the only possible oxidation number, as fluorine is the most electronegative element and doesn't loose electrons in any chemical reactions. Other halogens can have oxidation numbers: -1, +1, +3, +5 and +7.

All of them

N c r t

Don't know

Preparation of Hydrogen Chloride

Muriatic acid is prepared by warming NaCl crystals with concentrated H2SO4 (Sulphuric acid).

NaCl+H₂SO₄→NaHSO₄+HCl

Usually, most of the hydrogen chloride/hydrochloric acid that is formed is a co-product of some other chemical reactions. HCl is also formed by the chlorination of hydrocarbons.

Properties of Hydrogen Chloride

• HCl is an uncoloured gas and has a pungent aroma.

• Hydrochloric acid is the aqueous solution of hydrogen chloride.
• HCl is soluble in water.
• It liquefies at 189K to form a colourless liquid and freezes at 159k to form a white solid.

Uses of Hydrogen Chloride

• HCl is used in the preparation of chlorine, aqua regia, and other chlorides.
• It is used as a solvent to dissolve noble gases.
• It acts as a reagent in laboratories.

Hydrochloric acid is an inorganic chemical. It is a strong corrosive acid with a chemical formula HCl. It is also known as hydrogen chloride or muriatic acid.

Chemical properties of chlorine gas

1. Effect on litmus: Dry chlorine gas has no effect on litmus but the moist chlorine do have the effect, as it turns blue litmus red due to formation of HCl.
2. Reaction with metals and non metals: It reacts with metals and non metals to form respective chlorides that is given below:

Uses (Chlorine)

• It is used to get rid of the smell of putrefaction
• It is used as a disinfectant
• Chlorine is used in the treatment of drinking water to kill bacteria
• It is used to clean swimming pools
• It is used in the production of paper and paper products
• It is used as an antiseptic
• It is used to produce drugs
• It is used in the manufacture of dyes and plastics

The process by which modern organisms have descended from their ancestors, with changes in their allele frequencies, is called evolution.

The halogens are located on the left of the noble gases on the periodic table. These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Although astatine is radioactive and only has short-lived isotopes, it behaves similar to iodine and is often included in the halogen group. Because the halogen elements have seven valence electrons, they only require one additional electron to form a full octet. This characteristic makes them more reactive than other non-metal groups.

Introduction
Halogens form diatomic molecules (of the form X2​, where X denotes a halogen atom) in their elemental states. The bonds in these diatomic molecules are non-polar covalent single bonds. However, halogens readily combine with most elements and are never seen uncombined in nature. As a general rule, fluorine is the most reactive halogen and astatine is the least reactive. All halogens form Group 1 salts with similar properties. In these compounds, halogens are present as halide anions with charge of -1 (e.g. Cl-, Br-, etc.). Replacing the -ine ending with an -ide ending indicates the presence of halide anions; for example, Cl- is named "chloride." In addition, halogens act as oxidizing agents—they exhibit the property to oxidize metals. Therefore, most of the chemical reactions that involve halogens are oxidation-reduction reactions in aqueous solution. The halogens often form single bonds, when in the -1 oxidation state, with carbon or nitrogen in organic compounds. When a halogen atom is substituted for a covalently-bonded hydrogen atom in an organic compound, the prefix halo- can be used in a general sense, or the prefixes fluoro-, chloro-, bromo-, or iodo- can be used for specific halogen substitutions. Halogen elements can cross-link to form diatomic molecules with polar covalent single bonds.

Chlorine (Cl2) was the first halogen to be discovered in 1774, followed by iodine (I2), bromine (Br2), fluorine (F2), and astatine (At, discovered last in 1940). The name "halogen" is derived from the Greek roots hal- ("salt") and -gen ("to form"). Together these words combine to mean "salt former", referencing the fact that halogens form salts when they react with metals. Halite is the mineral name for rock salt, a natural mineral consisting essentially of sodium chloride (NaCl). Lastly, the halogens are also relevant in daily life, whether it be the fluoride that goes in toothpaste, the chlorine that disinfects drinking water, or the iodine that facilitates the production of thyroid hormones in one's body.

The halogens are located on the left of the noble gases on the periodic table. These five toxic, non-metallic elements make up Group 17 of the periodic table and consist of: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Although astatine is radioactive and only has short-lived isotopes, it behaves similar to iodine and is often included in the halogen group. Because the halogen elements have seven valence electrons, they only require one additional electron to form a full octet. This characteristic makes them more reactive than other non-metal groups. Halogens form diatomic molecules (of the form X₂​, where X denotes a halogen atom) in their elemental states. The bonds in these diatomic molecules are non-polar covalent single bonds. However, halogens readily combine with most elements and are never seen uncombined in nature. As a general rule, fluorine is the most reactive halogen and astatine is the least reactive. All halogens form Group 1 salts with similar properties. In these compounds, halogens are present as halide anions with charge of -1 (e.g. Cl^-, Br^-, etc.). Replacing the -ine ending with an -ide ending indicates the presence of halide anions; for example, Cl^- is named "chloride." In addition, halogens act as oxidizing agents—they exhibit the property to oxidize metals. Therefore, most of the chemical reactions that involve halogens are oxidation-reduction reactions in aqueous solution. The halogens often form single bonds, when in the -1 oxidation state, with carbon or nitrogen in organic compounds. When a halogen atom is substituted for a covalently-bonded hydrogen atom in an organic compound, the prefix halo- can be used in a general sense, or the prefixes fluoro-, chloro-, bromo-, or iodo- can be used for specific halogen substitutions. Halogen elements can cross-link to form diatomic molecules with polar covalent single bonds.

Fluorine differs from rest of the members of its group because of its small size, high electro negativity and non availability of d orbitals in the valence shell.

? small size ?High e negativity ?low bond dissociation enthalpy?absence of d orbital?

The halogen are reactive because of the outermost electrons of its shell, all atom wants to complete the electrons of the outermost shell with eight electrons or two. For the halogens it has 1 electron at it’s outermost shell and it wants to get rid of it that means it loses electrons easily to complete the octet rule. When it loses electrons easily, other atoms reacts or gains the electrons easily. Remember that gaining electrons releases energy.

 A lone pair is the  valence electron pair without bonding or withut sharing with other atoms. They are found in the outermost electron shell of an atom, so the lone pairs are a subset of a molecule's valence electrons. They can be identified by examining the outermost energy level of an atom—lone electron pairs consist of paired electrons as opposed to single electrons, which may appear if the atomic orbital is not full. Electron pairs are therefore considered lone pairs if two electrons are paired but are not used in chemical bonding. Thus, the number of lone electrons plus the number of bonding electrons equal the total number of valence electrons in a compound.

The strength of the chemical bond between any two species can be estimated with the help of bond dissociation enthalpy. Although it is generally measured as the enthalpy change at standard conditions (298K), the bond dissociation energy of a chemical bond is often defined as the enthalpy change of the homolytic fission of the bond at absolute zero (0K).

Some important features of the concept of bond dissociation enthalpy include:

• It is the amount of energy which needs to be supplied in order to break a chemical bond between two species.
• It is a means of calculating the strength of a chemical bond.
• In diatomic molecules specifically, it is equal to the value of bond energy
• The bond between silicon and fluorine is said to have the strongest bond dissociation enthalpy.
• Covalent bonds between atoms or molecules are said to have weak bond dissociation energies.

Halogens are coloured because of their low ionisation energy.

As a result, the electrons get excited in the visible region of light.

The remaining light falls in the visible region and halogens appear to be coloured.

For example: Fluorine absorbs wavelengths corresponding to violet light and the remaining light appears to be yellow. Thus, fluorine has a yellow colour. Similarly, chlorine is greenish yellow, bromine reddish and iodine is a violet solid.

The National Education Policy 2020 (NEP 2020), which was approved by the Union Cabinet of India on 29 July 2020, outlines the vision of India's new education system.[1] The new policy replaces the previous National Policy on Education, 1986.[a] The policy is a comprehensive framework for elementary education to higher education as well as vocational training in both rural and urban India. The policy aims to transform India's education system by 2040.[2] Shortly after the release of the policy, the government clarified that no one will be forced to study any particular language and that the medium of instruction will not be shifted from English to any regional language.[3] The language policy in NEP is a broad guideline and advisory in nature; and it is up to the states, institutions, and schools to decide on the implementation.[4] Education in India is a Concurrent List subject.[5]The NEP 2020 replaces the National Policy on Education of 1986.[a][6] In January 2015, a committee under former Cabinet Secretary T. S. R. Subramanian started the consultation process for the New Education Policy. Based on the committee report, in June 2017, the draft NEP was submitted in 2019 by a panel led by former Indian Space Research Organisation (ISRO) chief Krishnaswamy Kasturirangan. The Draft New Education Policy (DNEP) 2019, was later released by Ministry of Human Resource Development, followed by a number of public consultations.[7] The Draft NEP was 484 pages.[8] The Ministry undertook a rigorous consultation process in formulating the draft policy: "Over two lakh suggestions from 2.5 lakh gram panchayats, 6,600 blocks, 6,000 Urban Local Bodies (ULBs), 676 districts were received."[9]

Just go through Google you will get it.. ????

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kya hua yrr Sahil..... tu pata hai bohot moody hai?.....jaldi se gussa ho jata hai☹️