Chemistry Podcast

Thursday, 30 May 2019

ताप और तापमान

ताप और तापमान

गर्मी ( ताप या ऊष्मा) और तापमान के बारे में जानने के लिए। हम पहले यह समझने की कोशिश करते हैं कि गर्मी क्या है। फिर हम अध्ययन करते हैं, तापमान क्या है।

ऊष्मा क्या है ?

तापमान में अंतर के कारण ऊर्जा के आदान-प्रदान को ऊष्मा कहा जाता है। लेकिन संज्ञा के रूप में हम कह सकते हैं कि ऊष्मा गर्म या उच्च तापमान होने का गुण है और आसानी से समझने के लिए हम कह सकते हैं कि गर्म या गर्म होने का एहसास गर्मी है।

गर्मी या ऊष्मा

तापमान में अंतर के कारण ऊर्जा के आदान-प्रदान को ऊष्मा कहा जाता है। हम यह भी कह सकते हैं कि, ऊष्मा ऊर्जा का वह रूप है, जिसे दो पदार्थों के बीच अलग-अलग तापमान पर ले जाया जाता है। यदि दो पदार्थ संपर्क में हैं, और एक में 200K तापमान और अन्य में 100K तापमान है। फिर ऊर्जा, उच्च तापमान से निचले तापमान तक प्रवाहित होती है। तो उपरोक्त मामले में, गर्मी 200K तापमान वाले पदार्थ से 100K तापमान वाले पदार्थ तक बहती है। ऊष्मा ऊर्जा का एक रूप है। इसलिए ऊष्मा को ऊर्जा, आमतौर पर कैलोरी या जूल की इकाइयों में मापा जाता है।

तापमान क्या है?

तापमान किसी पदार्थ की गर्माहट या ठंडक की मात्रा है। बस हम कह सकते हैं कि, तापमान इस बात का माप है कि कोई वस्तु कितनी गर्म या ठंडी है।


तापमान में गर्माहट या ठंडक की मात्रा होती है। वैज्ञानिक तरीके से भी, तापमान को किसी पदार्थ के प्रति अणु की औसत गतिज ऊर्जा के रूप में समझाया गया है। गर्मी और तापमान दो अलग-अलग शब्द हैं और इनके अलग-अलग अर्थ हैं, इसलिए इन दोनों के बीच भ्रमित न हों। ऊष्मा ऊर्जा है, जबकि तापमान ऊर्जा नहीं है। ताप, जूल में मापा जाता है। जबकि तापमान सेल्सियस (C), फ़ारेनहाइट (F) या केल्विन (K) में मापा जाता है। गर्मी के लिए इस्तेमाल किया जाने वाला प्रतीक Q है, जबकि तापमान के लिए इस्तेमाल किया जाने वाला प्रतीक T। जूल है, जो ताप की SI इकाई है। जबकि तापमान की SI इकाई केल्विन है।

गर्मी Vs तापमान

ऊष्मा गर्म वस्तु से ठंडी वस्तु तक ऊर्जा का प्रवाह है जबकि तापमान इस बात का माप है कि कोई वस्तु कितनी गर्म या ठंडी है। ताप ऊर्जा है जबकि तापमान ऊर्जा नहीं है। ताप जूल में मापा जाता है, जबकि तापमान सेल्सियस (C), फारेनहाइट (F) या केल्विन (K) में मापा जाता है। गर्मी के लिए इस्तेमाल किया जाने वाला प्रतीक Q है जबकि तापमान के लिए इस्तेमाल किया जाने वाला प्रतीक T है। ऊष्मा का SIunit जूल है, जबकि तापमान का SI unit केल्विन है।
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Friday, 17 May 2019

12 Class Chapter 8 – d and f Block Elements

12 Class Chapter 8 – d and f Block Elements

d and f Block Elements

These chemistry notes of d and f block elements are provided by Chemistry Notes Info website to students. So in this chemistry notes article we learn about d and f block elements class 12 notes of chemistry.

d-Block Elements

Introduction to d-Block Elements

The d-block elements are defined as the elements from periodic table in which, last electron enters into the ‘d-orbital’ of the penultimate shell i.e. (n-1)d orbital. Where ‘n’ is the last shell.
The d-block elements are also called transition elements, because their properties are intermediate between the properties of highly electropositive s-block elements and highly electronegative p-block elements. Transition elements have partly or incompletely filled (n-1)d orbital in their elementary states.

Position in Periodic Table of d-Block Elements

  • d-block elements are placed between s-block elements and p-block elements. The elements are placed between group 3 to 12 belonging to the period 4 to 7.
  • There are four series of transition elements i.e. 3d,4d,5d and 6d series
  • The 3d series starts from Sc(z=21) to Zn(z=30) and belongs to 4th period.
  • The 4d series includes all the elements from Y(z=39) to Cd(z=48) and belongs to 5th period.
  • The 5th series starts with element La(z=57) and then includes all the elements from Hf(z=72) to Hg(z=80) and belongs to 6th period.
Thus 6d series starts from Ac(z=89) and then includes all the elements from Rf (z=104) to Unb(z=112) which belong to 7th period.

Electronic Configuration d-Block Elements

General electronic configuration of four series of d-block elements are given below.
  1. 3d series:[Ar] 3d1-10  4S1-2
  2. 4d series :[Kr] 4d1-10  5S0-2
  3. 5d series :[Xe] 5d1-10   6S2
  4. 6d series :[Rn] 6d1-10  7S2

Abnormal Electronic Configuration of Chromium And Copper among d Block Elements

  • Chromium(24Cr) has electronic configuration
(Expected):[Ar] 3d 4S2
(Observed):[Ar] 3d5 4s1
  • Copper (29Cu) has electronic configuration
(Expected):[Ar] 3d9 4s1
(Observed):[Ar] 3d10 4s1
Explanation: due to more stability of half –filled and completely filled orbital.

Occurrence of d Block Elements

The soft elements of d-block or transition occur as sulphide minerals. Hard and electropositive elements occur as oxide.

General Characteristics of d-Block Elements

All the transition elements are metal having high melting as well as boiling point. They are good conductors of electricity and heat. They form complexes and colored compound.
Due to unpaired electrons most of the elements are paramagnetic while some exhibit diamagnetic character. They are good catalyst and they form alloys with different metals.

General Trend in Properties Of First Row Elements of d Block

Ionization Enthalpy

  • The ionization enthalpies of transition elements are quite high and lie between those of s-block and p-block elements. This is because the nuclear charge and atomic radii of transition elements lie between those of s-block and p-block elements.
  • If IE1, IEand IE3 are the first, second and third ionization enthalpies of transition elements then IE<IE2<IE3.
  • The ionization enthalpies value of transition metal can be used to predict thermodynamic stability of their compound.
Metallic Character
  • All the transition metals have high thermal as well as electrical conductivity and having very high melting and boiling points compared to those of representative elements due to their closed-packed structure.
  • On going across the period melting points first increase, attain maximum value and then steadily decreases as atomic number.
  • The strength of metallic bond depends upon the number of unpaired electrons, it increases up to middle i.e., up to (n-1)d5 hence accordingly melting and boiling points also increases.
  •  After (n-1) d5 configuration, the electrons starts pairing ,hence metallic strength, melting and boiling points decreases with increase in atomic number.

Oxidation States

  • The transition metal exhibit variable oxidation states and form compounds showing more than one (variable) oxidation states because energies levels of ns and (n-1)d are nearly similar. The oxidation state of 3d series is from +2 to +7 (except Cr and Cu).
  • The lowest oxidation states of these elements are +1 or +2 which is due to their 4s electrons.
  • As the number of unpaired electrons in 3d orbital increases the number of oxidation state also increases form Sc to Mn and after that electrons starts pairing in 3d orbital hence oxidation states decreases form Fe to Zn.
  • The highest oxidation state of transition elements is +8 which shown by Os and Ru.

Atomic and Ionic Radii

  • Atomic radii of the elements of 3d series gradually decreases up to  Cr  and then remain almost same for a few more elements and then increases slightly towards the end of end of the series.
  • In 3d series the decreases in atomic radii is small from Sc to Cr because increase in nuclear charge at the centre of atom and added electrons filled up in vacant penultimate d orbital, atomic    
  •   radii from Cr to Cu are almost similar and then slightly increases to Zn
  • Ionic radii also follow similar trend as observed in the atomic radii values.


  • Most of the compounds of transition metals are coloured in their solid or solution form. Colour of the compound of the transition metals may be attributed to the presence of incomplete (n-1)d orbital and the number of unpaired electrons.
  • Transition metal ions with no unpaired electrons are colourless because there is possibility of d-d transition. e.g. Sc+3(3d0), Ti+4(3d0), Cu+(3d10). Ions with unpaired electrons are coloured i.e. ions with electronic configuration 3d1 to 3d9 are coloured.
  • In general, the colour of transition ions can be related to –    
    • Presence of unpaired d electrons.
    • d-d transition.
    • Nature of groups i.e. ligands linked to metal ions.
    • Geometry of the complexes formed by the metal ion.

Catalytic Properties

  • Many transition metals are used as catalysts which influence the rate of chemical reaction.
  • A catalytic substance is capable of forming an unstable intermediate compound which readily decomposes yielding the products and regenerating the catalyst.
A+B       +     C        —–>   [A-B-C]     —–>       A-B       +      C
(reactant)   (catalyst)       (intermediate)        (product)     (catalyst)
  • The commonly used transition metals as a catalyst are Fe, Co, Pt, Cr, Mn etc.
  1. Mno2 acts as a catalyst for decomposition of KCloto O2.
  2. In manufacture of ammonia, Fe with Mo is used as catalyst.
  3. Nickel acts as a catalyst in hydrogenation of oils to fats.

Magnetic Properties

  • Due to presence of unpaired electrons in the (n-1)d orbital, most of the transition metal ions and their compounds are paramagnetic i.e. they are attracted by magnetic field.
  • The transition element and their ions having all electrons paired are diamagnetic i.e. they are repelled by magnetic field.
  • Metals like Fe, Co and Ni posses very high paramagnetic and acquire permanent magnetic moment hence, they are ferromagnetic.
  • Alnico is an alloy of Al(12%), Ni(20%),Co(50%) and remaining Fe(18%). It is used to make permanent magnets.
  • Bohr magneton (B.M) is unit of magnetic moment:   
1B.M = eh/4πmec
  • The effective magnetic moment µeff, of a paramagnetic substance is given by ‘spin only’ formula.
Where n is the number of unpaired electrons.

Alloy Formation

  • The transition metals can form large number of alloys among themselves having high melting points.
  • In the molten state, transition metals are miscible with one another, which forms solid alloy on cooling.
  • Transition metals can form alloy with non transition metals such as brass (Cu-Zn) and bronze (Cu-Sn).


Properties of Potassium Dichromate

Potassium Dichromate exists as orange red crystals and is soluble in water.

Action of Alkali

Alkali (KoH) reacts with potassium dichromate to give yellow coloured solution of potassium chromate.
K2Cr2O7  + 2KOH  ——>  2K2CrO+ H2O.

Oxidizing Properties

Potassium Dichromate is good oxidizing agent in acidic medium. Potassium dichromate (oxidation number of  Cr = +6) is reduced to chromium sulphate (oxidation number of Cr = +3)
CrO72-  +  14H+  +   6e ——> 2cr3+   +  7H2O.
By gaining six electrons dichromate ions acts as an oxidizing agent.

Structure of Chromate Ion and Dichromate Ion

Uses of Potassium Dichromate

  1. It is used as an oxidizing agent.
  2. Used in a dyeing.
  3. In manufacture of lead chromate and chrome alum.
  4. Used in the detect ion of chloride ion.
  5. In the tanning of leather.
  6. In manufacture of pigments and inks.


Properties of KMnO4

  • It is crystalline solid having deep purple colour. It is soluble in water at room temperature.
  •  When heated it decomposes giving oxygen at 473K.
           2KMnO4   —–>  K2MnO  +  MnO + O2
  • At red heat, it further decomposes to K2MnO3 and oxygen.
  • Heated solid KMnO4 gives KOH, MnO and water vapour in current of H2.

Structure of Manganate Ion and Permangate Ion

Uses of KMnO4

It is used as –
  1. Disinfectant.
  2. An oxidizing agent.
  3. Baeyer’s reagent.
  4. For detecting halides in qualitative analysis.

f-Block Elements

Introduction to f-Block Elements

The elements in which differentiating electrons (last electrons) enters into pre-penultimate shell i.e. (n-2)f orbital are known as f block elements. f block elements are also known as inner transition elements.
There are two series of inner transition elements i.e. lanthanoid series (4f block elements) and actinoid series (5f block elements).

Lanthanoid Series

  • This includes all the elements from cerium (z=58) to lutetium (z=71) which are group of 14 elements with differentiating electron occupying 4f sub shell.
  • The name lanthanoid has been derived from lanthanum which is prototype of lanthanoid.
  • Lanthanoid series are also called 4f series because last electron enters pre-penultimate in 4f orbital.

Position of Lanthanoids

  • Lanthanoids belongs to group 3 of periodic table and are placed in the sixth period.
  • Lanthanoids are shown at the bottom of the periodic table because it interrupts third transition series of d-block elements.
  • Actual position of lanthanoids is in between (z=57) and hafnium (z=72).

Electronic Configuration of Lanthanoids

  • The general electronic configuration of 4f block elements is
[xe] 4f1-14 5d0-1 6s2 
  • Elements La, Gd, Lu posses single electrons in 5d sub shell. In case of other lanthanoids 5d orbital is empty.
  • Due to empty, half filled and completely filled orbital f0, fand f14 electronic configuration elements achieve extra stability.

Oxidation States of Lanthanoids

  • The common oxidation state of all lanthanoids is +3. It is characteristics of series.
  • Lanthanum, gadolinium and lutetium shows only +3 oxidation state by losing two 6s and one 5d electrons giving stable outer electronic configuration 4f0,4f7 and 4f14 respectively.
  • In +4 oxidation state cerium, terbium attains 4f0 and 4f7 respectively.
  • Europium (Eu) as well as ytterbium (Yb) attains 4f7 and 4f14 respectively in +2 oxidation state.

Chemical Reactivity of Lanthanoids

  • Earlier members of lanthanoids are quite reactive, behaves like calcium but as atomic number increases, they behaves more like aluminium.
  • Lanthanoids forms carbides, hydrides, oxides, nitrides, halides, etc.
  • Carbides-
Ln   +   C    —->    Lanthanoid  Carbide
  • Hydrides-
2Ln  +  3H2   —->  2LnH3
  • Oxides-
2Ln   +  3O2   —->  2Ln2O3
  • Nitrides-
2Ln  +  N2    —->   2LnN
  • Halides-
2Ln   +   6HCl   —->  2LnCl3  +  3H2
  • Sulphides-
2Ln   +  3S   —–>   Ln2S3

Lanthanoid Contraction

The gradual decrease in atomic and ionic size of lanthanoids with increases in atomic number is called lanthanoid contraction. You read these notes under 12 class chemistry notes of chapter d and f block elements.

Causes of Lanthanoid Contraction

  • Increases in atomic number of member of lanthanoids series, the positive charge on nucleus increases by +1 unit and one more electron enters in the pre-penultimate 4f sub shell. There is imperfect shielding of one electron by another electron in the same 4f sub shell.
  • With increase in nuclear charge the valence shell is pulled slightly towards nucleus. As a result of the pull, the size of M3+ ions goes on decreasing with increasing in atomic number.
  • In complete lanthanoid series atomic radii and ionic radii decreases with 10 pm and 21 pm respectively. Atomic radii shows some irregularities but ionic radii decreases steadily.

Effects of Lanthanoid Contraction

  • Decrease in Basicity
Due to lanthanoid contraction the size of the tri-positive lanthanoid ion (M3+) regularly decreases with increase in atomic number i.e. from La3+ to La3+. It results into decrease of basic from La3+ to Lu3+.
  •  Ionic Radii of the Post Lanthanoids
The elements which follow the lanthanoids in the third transition series are known as post lanthanoid. As a result of lanthanoid contraction the atomic radii (size) of the elements which follow lanthanum (Hf, Ta, W, etc) are similar to that of the elements of 4d series. Since Zr-Hf, Nb-Ta, Mo-W and Tc-Re have almost identical sizes, similar number of valence electrons and similar properties these pairs of elements are called chemical twins.

Actinoid Series

  • The series of fourteen elements 90Th to 103Lr which follows actinium (89Ac) and in which last electrons are progressively filled in 5f orbital in pre-penultimate shell are called actinoid series or 5f series.
  • The elements which are synthetically or artificially prepared by man having atomic number higher than uranium (z=92) are called as trans-uranic  elements (Np-93 to Uno-118).

Position of Actinoids

  • The actinoids belongs to third group of the periodic table in the seventh period.
  • Actinoids are placed at the bottom of the periodic table below the lanthanoid series because it interrupts fourth transition series of d-block elements.

Electronic Configuration

  • The general electronic configuration of 5f elements is represented as 5f1-14 6d0-1 7s2.
  • The electronic configuration of actinoids is not definite.
  • Actinium and thorium does not contain any 4f electron.

Oxidation States of Actinoids

  • Actinoid show varied oxidation states like lanthanoids. The common oxidation states of actinoids is 3+. Ac, Th and Am shows +2 oxidation states. Th, Pa, U, Np, Pu, Am and Cm shows +4 oxidation states.
  • +5 oxidation state is shown by element Th to Am. U, Np, Pu and Am show oxidation state +6.The highest oxidation state is +7 shown by Np and Pu.

How To Actually Learn More D And F Block Elements

In these notes you understand, How To Actually Learn More about D And F Block Elements. You just completed learning of d block elements and f block elements of 12 class chapter 8 d and f block elements. Also learn about p Block Elements on
Also read our other chemistry Notes of Class 12 under category 12th Class Chemistry Notes
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Sunday, 5 May 2019

How Medicines are Manufactured?

How Medicines are Manufactured?

In ancient times people use plants or animals matter to cure some sort of ailment or diseases by using home remedies. But now day’s medicine manufacturing is performed by chemical processing. Scientists first finds chemicals in plants or animals with their years of research and knowledge, then isolate these chemicals and try to make artificial chemical like original source chemical taken from plant or animals. After getting succeeded in making artificial synthetic chemical that cure targeted ailment or diseases, scientists start making medicines.

Now question is what a medicine contains? So medicines contain active drug called API (Active Pharmaceutical Ingredients) and excipient. API is active drug in any medicine which has therapeutic action to cure targeted ailment or diseases or disorder. While excipient is the non-active ingredient to support and enhance activity of drug product.

Where these medicines are manufactured?

Medicines are manufactured in Pharmaceutical manufacturing companies like Cipla, Glenmark, Lupin, Wockhardt, Alembic, Zydus, Mylan etc. First drug API is manufactured in API processing plants and then medicines are manufactured in Formulation plants by using API drugs and excipients.  Medicines are manufactured in different dosage forms like OSD (Oral Solid Dosage) tablets, capsules, Liquid Syrups, Injectable etc. Means you get medicines prescribed by your doctor in forms like tablets, capsules, liquid syrups, injections. These medicines are manufactured under GMP (Good Manufacturing Practices) controlled environment. During medicines manufacturing temperature, humidity and air pressure is maintained by AHU (Air Handling Unit) to provide controlled environment and also to prevent cross contamination.

API Manufacturing Plant

API plants have different departments for dedicated function like Warehouse Department for storage receive, dispensing and dispatch of materials. Production Department or API Plant where batch (Batch is a specific quantity of a drug or other material that is intended to have a uniform character and quality, within specified limits, and is produced according to a single manufacturing order during the same cycle of manufacturing.) processing happen, means chemical reactions are performed as per Batch Records and SOPs (Standard Operating Procedure) in chemical reactors.
Quality Control Department or QC Lab where testing of samples is performed. QC Sampling is a process of abstraction of a portion of material from a lot or a batch in such a way that the withdrawn sample is representative of that whole lot or batch. QC person perform testing by taking samples at different stages of API manufacturing. Quality Assurance Department for taking assurance of quality of manufactured API during processing. HR, Admin, IT, Finance, RA, CQA are other supporting departments.

Formulation Plant
Formulation plants also have different departments just like API manufacturing plants. Warehouse for storage, control, dispense and dispatch of materials and products. Production Department where medicines are produced, Different type of machines are used in production plants to make medicines like Isolators, Blending machine, compression machine, coating machine, granulation machine, capsule filling machine, inspection machine etc. are used to make medicines.

Packing Department where packaging of medicines is performed with the help of different machines. Blister machine, Bottle filling Counter machine, checkweigher, Unscrambler, Desiccant Sachet inserter, Cottoner, Capper Sealer, Labeller, CAM cartonator, Printer, Shipper Sealer are some machine used in packing department.
Quality Control Department or QC Lab where testing of samples is performed. QC person take sample during batch processing from different stages of manufacturing and analyse these sample in chemical labs using HPLC, GC, distillation, chromatography, titration and many more advance testing methods. Quality Assurance Department for taking assurance of quality of manufactured medicines. Safety Department to take care about safety of property building and peoples working in pharma industry

Drug development: journey of a Medicine manufacturing

During manufacturing medicines goes through different stages to become finished goods. First API and Excipient is dispensed by warehouse to production. Then these are mixed filtered and processed to produce intermediate product (A partly processed material, which undergoes further processing before it becomes a finished product). Then this intermediate product is processed further to produce finished product.

Finished product is a product that has completed all stages of manufacturing, and now this finish product is ready for packing. Now packing department perform packaging of finish product into finished goods. Finished goods are products that has completed all packing stages and packed into the final pack, as a result now ready for dispatch.
Dispatched finished goods are now become medicine after several processing testing manufacturing and packaging stages. Manufacturing of medicines is regulated by Regulatory Bodies around the world like USFDA (Unites States Food and Drug Administration from United States), WHO (World Health Organization), MHRA (Medicines and Healthcare Products Regulatory Agency from United Kingdom), CDSCO (Central Drug Standard Control Organization from India), TGA (Therapeutic Goods Administration from Australia), TPD (Therapeutic Product Directorate from Canada), EMA (European Medicines Agency from Europe) etc. Every manufactured medicine has manufacturing date, expiry date and shelf life. So now we understand these terms more clearly means what is manufacturing date, expiry date and shelf life.

What is Manufacturing Date?

Manufacturing date of the batch is the date on which actual batch activity is started so dispensing is always the first activity during any batch processing. So date of dispensing is considered as the manufacturing date.

What is Expiry Date?

Expiry date is the date till which a drug product is expected to remain within its approved specification. Or simply it is the date up to which the medicine is useful for its intended action.

What is Shelf Life?

Shelf life of medicine is a period of time during which a medicinal product or medicine, when stored properly under environments defined on the label is expected to comply with established specification. Or simply it is the time period up to which the medicine is useful for its intended action.
So today we learn what is medicine and how it is manufactured at Chemistry Notes Info. In upcoming posts we learn more about medicine manufacturing. Do you know what is GMP and why it is necessary during medicine manufacturing.

Books to learn how pharma drug medicines are manufactured

  1. cGMP Current Good Manufacturing Practices for Pharmaceuticals, 2nd Edition
  2. Handbook of Pharmaceutical Manufacturing Formulations: Volume Three, Liquid Products
  3. An Unfinished Agenda: My Life in the Pharmaceuticals Industry


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