ACTIVITY SERIES OF METALS

Potassium > Sodium > Calcium > Magnesium > Aluminium > (Carbon) > Zinc > Iron > Tin > Lead > (Hydrogen) > Copper > Mercury > Silver > Gold > Platinum

Note - that Carbon and Hydrogen are non-metals, used as a baseline

 s-Block Elements:

Covalent Character:.

Small cation and large anion favors covalency.

Order: LiCl > NaCl > KCl > RbCl > CsCl & . LiI > LiBr > LiCl > LiF

Greater the charge on the cation greater is its polarizing power and hence larger is the covalent character: Na+CI- < Mg+2CI2 < AI+3 CI3              

Greater the charge on the anion, more easily it gets polarized thereby imparting more covalent character to the compound formed eg covalent character increase in the order. NaCI < Na2SO4 < Na3PO4 

c) Lattice Energies: Amount of energy required to separate one mole of solid ionic compound into its gaseous ions. 

Greater the lattice energy, higher is the melting point of the alkali metals halide and lower is its solubility in water

d) Hydration Energy: Amount of energy released when one mole of gaseous ions combine with water to form hydrated ions.

M+ (g) + aq → M+ (aq) + hydration energy

X- (g) + aq → X- (aq) + hydration energy     

Higher the hydration energy of the ions greater is the solubility of the compound in water.

The solubility of the most of alkali metal halides except those of fluorides decreases on descending the group since the decrease in hydration energy is more than the corresponding decrease in the lattice energy.

Due to high hydration energy of Li+ ion, Lithium halides are soluble in water except LiF which is sparingly soluble due to its high lattice energy.

For the same alkali metal the melting point decreases in the order

fluoride > chloride > bromide > iodide

For the same halide ion, the melting point of lithium halides are lower than those of the corresponding sodium halides and thereafter they decrease as we move down the group from Na to Cs.

The low melting point of LiCl (887 K) as compared to NaCl is probably because LiCl is covalent in nature and NaCl is ionic.

Anomalous Behavior of Lithium and diagonal relationship with Magnesium:

Li has anomalous properties due to

Very small size

High polarizing Power

Lithium show diagonal relationship with magnesium because both  elements have almost same polarizing power.

The melting point and boiling point of lithium are comparatively high.

Lithium is much harder than the other alkali metals. Magnesium is also hard metal.

Lithium reacts with oxygen least readily to form normal oxide whereas other alkali metals form peroxides and superoxides.

LiOH like Mg (OH)2  is weak base. Hydroxides of other alkali metals are strong bases.

Due to their appreciable covalent nature, the halides and alkyls of lithum and magnesium are soluble in organic solvents.

Unlike elements of group 1 but like magnesium. Lithium forms nitride with nitrogen.6Li + N2 → 2Li3N       

LiCl is deliquescent and crystallizes as a hydrate, LiCI2H2O. Other alkali metals do not form hydrates.  also forms hydrate, MgCI2.8H2O .

Unlike other alkali metals lithium reacts directly with carbon to form an ionic carbide. Magnesium also forms a similar carbide.

The carbonates, hydroxides and nitrates of lithium as well as magnesium decompose on heating.

Li2CO3 → Li2O + CO2

MgCO3 → MgO + CO2

2LiOH → Li2O + H2O

Mg (OH)2  → MgO + H2O

4LiNO3 → 2Li2O + 4NO2 + O2

2Mg ( NO3)2 → 2Mg + 4NO2 +O2 

The corresponding salts of other alkali metals are stable towards heat. 

Lithium nitrate, on heating, decomposes to give lithium oxide, Li2O  whereas other alkali metals nitrate decomposes to give the corresponding nitrite.

4LiNO3 → 2Li2O + 4NO2 + O2  

2NaNO3 → 2NaNO2 + O2               

2KNO3 → 2KNO2 + O2   

Li2CO3, LiOH, LiF and Li3PO4   are the only alkali metal salts which are insoluble in water. The corresponding magnesium compounds are also insoluble in water.

Hydrogen carbonates of both lithium and magnesium can not be isolated in solid state. Hydrogen carbonates of other alkali metals can be isolated in solid state.

 Sodium Hydroxide (NaOH):  

a. Properties

NaOH is stable towards heat but is reduced to metal when heated with carbon

2NaOH + 2C → 2Na +2CO + H2

FeCl3 + 3NaOH →Fe(OH)3 + 3NaCl

NH4Cl + NaOH → NaCl + NH3 (pungent smell) + H2O

Father of various subjects/faculties

Father of History : Herodotus

Father of Mathematics : Archimedes

Father of Economics : Adam Smith

Father of Botany : Theophrastus

Father of C language : Dennis Ritchie

Father of Geometry : Euclid

Father of Biology : Aristotle

Father of Blood groups : Landsteiner

Father of Ayurveda : Charaka

Father of Electronics : Ray Tomlinson

Father of Medicine : Hippocrates

Father of Physics : Albert Einstein

Father of Robotics : Nikola Tesla

Father of Homeopathy : Samuel Hahnemann

Father of Internet : Vinton Cerf

Father of Law : Cicero

Father of Algebra : Diophantus

Father of Architecture : Imhotep

Father of Genetics : Gregor Johann Mendel

Father of Electricity : Benjamin Franklin

Father of Microbiology : Louis Pasteur

Father of Modern Chemistry : Antoine Lavoisier

Father of Trigonometry : Hipparchus

Father of Nanotechnology : Richard Smalley

Father of Periodic table : Dmitri Mendeleev

Father of Search engine : Alan Emtage

Father of the American Constitution : James Madison

Father of the Green Revolution in India : M.S Swaminathan

Father of Statistics : Ronald Fisher

Father of Surgery (early) : Sushruta

Father of Taxonomy : Carolus Linnaeus

Father of Robotics :; Al-Jazari

Father of Video game : Thomas T. Goldsmith, Jr.

Father of World Wide Web : Tim Berners-Lee

Father of Zoology : Aristotle

Father of the Green Revolution : Norman Ernest Borlaug

Ammendments in indian flag code - Har Ghar Tiranga

पहले तिरंगा फहराने का ये नियम

यह नियम था कि जब राष्ट्रीय ध्वज को खुले स्थान पर फहराया जाता है तो जहां तक संभव हो इसे सूर्योदय और सूर्यास्त तक ही फहराया जाना चाहिए,चाहे फिर मौसम कैसा भी हो.

                गृह सचिव ने अपने पत्र में कहा कि यह कदम नागरिकों को ‘हर घर तिरंगा’ समारोह में हिस्से लेने और अपने घरों में राष्ट्रीय ध्वज को फहराने के लिए प्रोत्साहित करने के उद्देश्य से उठाया गया है. इस वर्ष हम आजादी का अमृत महोत्सव मना रहे हैं आइए हम हर घर तिरंगा आंदोलन को मजबूत करें. 13 से 15 अगस्त के बीच घर में तिरंगा फहराएं. केंद्रीय गृह सचिव ने अपने पत्र में कहा कि सरकार को उम्मीद है कि 13 अगस्त को करीब 30 करोड़ घरों में तिरंगा फहराया जाएगा.

अब तिरंगा फहराने का ये नियम-

आजादी का अमृत महोत्सव' के तहत 'हर घर तिरंगा' अभियान शुरू करने की तैयारी कर रही केंद्र की मोदी सरकार ने एक अहम फैसला लिया है। स्वतंत्रता के 75वें वर्ष में देश के ध्वज कानून में बदलाव किया गया है। केंद्र सरकार ने लोगों को अपने घरों या खुले स्थानों पर दिन और रात, दोनों समय तिरंगा फहराने की अनुमति दी है।

अब पॉलिएस्टर से बने तिरंगे का भी इस्तेमाल किया जा सकता है

वहीं एक अन्य अहम फैसले के तहत अब पॉलिएस्टर और मशीन से बने राष्ट्रीय ध्वज का भी उपयोग किया जा सकता है। झंडा कानून में बदलाव में कहा गया है कि राष्ट्रीय ध्वज हाथ से काता जाएगा और हाथ से बुना या मशीन से बनाया जाएगा। यह कपास/पॉलिएस्टर/ऊन रेशमी खादी से बना होगा। पहले मशीन और पॉलिएस्टर से बने तिरंगे के इस्तेमाल की अनुमति नहीं थी।

अजय भल्ला ने लिखा, 'राष्ट्रीय सम्मान के अपमान को रोकने के लिए भारतीय ध्वज संहिता 2002 और अधिनियम, 1971 के तहत तिरंगे का प्रदर्शन, फहराना और उपयोग किया जाता है। इसके कुछ प्रावधानों में 20 जुलाई 2022 से बदलाव किया गया है। इसके तहत व्यक्ति अपने घर पर या खुले स्थान पर दिन और रात दोनों समय तिरंगा फहरा सकेगा।'

बता दें, मोदी सरकार ने 'हर घर तिरंगा' अभियान का ऐलान किया है। इसके तहत अगले महीने 13 से 15 अगस्त तक हर घर पर तिरंगा फहराने की अपील की गई है। सरकार का दावा है कि इस दौरान 20 करोड़ घर में राष्ट्रीय ध्वज फहराया जाएगा। इससे युवाओं में देश प्रेम की भावना पैदा होगी। वहीं कांग्रेस इस पहल का भी विरोध कर रही है।

Click here to see/download Flag code pdf 2022 in english

Click here to see/download Flag code pdf 2022 in hindi

RE-EVALUATION FOR CBSE CLASS - X EXAMINATIONS

RE-EVALUATION FOR CBSE CLASS - X EXAMINATIONS, TERM — II, 2021- 2022

Cbse has released schedule of re-evaluation of the answer book of class X

 CBSE is having a well-settled system of assessment, however, if the students are not satisfied with their evaluation, they are provided an opportunity for verification of marks, and a facility to obtain the Photocopy of their evaluated answer books, and the re-e\Valuation of their answers. Students using these facilities are requested to read the guidelines for availing these facilities carefully before applying to avoid any inconvenience later.

Accordingly, given below are the Modalities and Schedule for Secondary School Examination (Class X), Term-II, 2021-2022 for the processes of

i) Verification of Marks

ii)Obtaining (Scanned) Photocopy of the Evaluated Answer Book(s)

ii) Re-evaluation of Answer(s)

The detailed modalities for applying for Verification of Marks, Obtaining Photocopy of the Evaluated Answer Book(s), and Re-evaluation of the answers for the candidates who have appeared for the Secondary School Examination (Class X) Term-II, 2021-2022 are as given below:

1.Requests for all the processes will be accepted only Online and during the specified schedules along-with processing charges. No application after the scheduled  date and time and in offline mode will be accepted.

2.The processing charges can only be deposited online (Credit/Debit Card Net Banking). Processing charges shall not be accepted through Postal Order& Money orderCheque/Cash etc.

3.Incomplete/offline applications will be summarily rejected without any correspondence with the candidate.

4.Only a single application for each step per  candidate  will  be  accepted  in  the  online process. The candidate must decide in advance whether he/she has to apply for one subject or multiple subjects.

5.Board will not be responsible for any consequences due to revision of mark(s) or delay in the process, for reasons beyond control.

6.Decrease even by one mark shall be affected.

7.In cases where there is a change in marks (both increase or decrease), such candidates shall have to surrender the Marksheet cum Certificate which is in their possession. Thereafter, they shall be issued a new Marksheet cum Certificate.

8.Processing charges are non-refundable.

I)VERIFICATION OF MARKS  

a.Schedule is given in Annexure-I. Processing charges are Rs.500/- per subject.

b.The outcome of the verification of marks will be communicated in the same login account of the candidate from where she/he has applied for verification in the following manner:

(i)   The outcome of the verification of marks will be uploaded to the login account of the candidate on the CBSE website. No individual communication will be sent in this regard.

(ii)   In case of a change in marks, the first communication that marks have been changed (increase/decrease in marks) will  be  provided/hosted.

(iii) Thereafter, once the result is re-calculated, the actual increase or actual decrease of marks will also be provided/hosted.

(iii) The applicants are advised to v iSit CBSE’s website for the status of the verification request.Website: www.cbse.gov.in, www.cbse.nic.in

b)   ONLY THOSE CANDIDATES WHO WILL APPLY FOR VERIFICATION OF MARKS ONLINE WILL BE ELIGIBLE TO APPLY FOR OBTAINING PHOTOCOPY OF ANSWER BOOK(S) IN THAT THOSE SUBJECT(S).

(II)    APPLICATION FOR OBTAINING A PHOTOCOPY OF THE EVALUATED ANSWER BOOK

a) Only those candidates who have applied for Verification of Marks Online in a manner as prescribed above will be eligible to apply for obtaining a photocopy of the evaluated answer book(s).

b) Processing charges will be Rs. 500/- per subject for Class-X. The schedule is given in Annexure-I.

c)  Application submitted on behalf of the candidate and also the incomplete application will be summarily rejected and fees deposited shall be forfeited without any further reference.

d) Applicants will be provided a scanned copy of the Answer Book in their login account after blocking all information relating to the identity of the Examiner/Evaluator/ any other official associated with the examination process etc.

e)   IF THE CANDIDATE DESIRES TO CHALLENGE THE  MARKS AWARDED TO ANY QUESTION, THEN H HE WILL HAVE TO APPLY ONLINE (AS PER THE SCHEDULE) FOR  RE-EVALUATION  OF MARKS.

(III)   RE-EVALUATION OF EVALUATED ANSWER BOOK (S)

(a)   Only those candidates who ha\ie applied for obtaining a photocopy of the evaluated answer book shall be eligible to apply for re-e\Valuation or challenge the marks awarded to any question(s).

(b)  Request for re-evaluation/challenges shall be accepted only for the theory portion @ Rs.100/- per question.

             c)   The applicant will have to refer to the marking scheme in the subject concerned which would be available on the website along with the question paper. Thereafter, candidates can submit an application for revaluation in the required question(s) with reasoning.

           (d)      Status of revaluation shall be uploaded on the website followed by a formal communication from the Regional Office.

            (e)     Decrease even by one mark shall be affected.

            (f} Result of the re-evaluation will be final and no appeal or review against the re-evaluation would be entertained.

 In the case of all the above three activities, i.e. I, II, and III, the decision of the Board on the marks awarded shall be final and binding on the candidates. 

Photocopy of the Answer Book (s) under RTI-Act-2005 will be provided as per provisions of RTI Act, 2005. However, a request for verification and/or re- evaluation cannot be made under RTI Act and shall not be entertained

SCHEDULE FOR VERIFICATION OF MARKS, OBTAINING PHOTOCOPY OF EVALUATED ANSWER BOOKS AND RE-EVALUATION FOR CLASS - X EXAMINATIONS, TERM — II, 2021- 2022

S.No.	Activity	Duration	Fee
1	VERIFICATION OF MARKS (APPLYING ONLINE)	26/07/2022 To 28/07/2022 upto Midnight 11:59:59	Rs.500/-per subject
2	OBTAINING PHOTOCOPY OF EVALUATED ANSWER BOOKs (APPLYING ONLINE)	08/08/2022   To   09/08/2022 upto Midnight 11:59:59	Rs.500/-per subject
3	RE-VALUATION (APPLYING ONLINE)	13/08/2022 To   14/08/2022 upto Midnight 11:59:59	Rs.500/-per subject

CBSE class 10 final result

CBSE Result class 12 2022