The document discusses shielding and screening in atoms. Shielding refers to the reduction of the true nuclear charge on the atom's nucleus by the electrons in other orbitals. Screening is the same concept as shielding. The effective nuclear charge (Zeff) experienced by an electron is calculated as Zeff = Z - σ, where Z is the atomic number and σ is the shielding constant. While the energy of an electron is proportional to Z2/n2, the energy required to remove an electron does not continuously increase with atomic number due to shielding effects of inner electrons.
Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm
Organic chemistry has two main divisions. One division deals with aliphatic (fatty) compounds, the first compounds you encountered in Organic Chemistry I. The second division includes the aromatic (fragrant) compounds, of which benzene is a typical example.
Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm
Organic chemistry has two main divisions. One division deals with aliphatic (fatty) compounds, the first compounds you encountered in Organic Chemistry I. The second division includes the aromatic (fragrant) compounds, of which benzene is a typical example.
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
NQR - DEFINITION - ELECTRIC FIELD GRADIENT - NUCLEAR QUADRUPOLE MOMENT - NUCLEAR QUADRUPOLE COUPLING CONSTANT - PRINCIPLE OF NQR - ENERGY OF INTERACTION - SELECTION RULE - FREQUENCY OF TRANSITION - APPLICATIONS
An overview of the use of the Marcus Theory to calculate the energies of transition states.
Contributed by: Elizabeth Greenhalgh, Amanda Bischoff, and Matthew Sigman, University of Utah, 2015
It is about molecular orbital theory specially mo diagram of diatomic atoms,their bond orders,bond lengths and stability and experimental evidences of ionisation energy from PES.
this presentation discusses the crystal field theory and its role in explaining the formation of coordination complexes by transition elements, their magnetic and colour properties; and its limitations!
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
NQR - DEFINITION - ELECTRIC FIELD GRADIENT - NUCLEAR QUADRUPOLE MOMENT - NUCLEAR QUADRUPOLE COUPLING CONSTANT - PRINCIPLE OF NQR - ENERGY OF INTERACTION - SELECTION RULE - FREQUENCY OF TRANSITION - APPLICATIONS
An overview of the use of the Marcus Theory to calculate the energies of transition states.
Contributed by: Elizabeth Greenhalgh, Amanda Bischoff, and Matthew Sigman, University of Utah, 2015
It is about molecular orbital theory specially mo diagram of diatomic atoms,their bond orders,bond lengths and stability and experimental evidences of ionisation energy from PES.
this presentation discusses the crystal field theory and its role in explaining the formation of coordination complexes by transition elements, their magnetic and colour properties; and its limitations!
Modern Periodic Law,Classification of Elements, Periodicity in Atomic Properties,Atomic Radius, Ionisation potential or Ionisation Energy,Electron Affinity
How long could one survive in a perfectly airtight room.docxMithil Fal Desai
How long could one survive in a perfectly airtight room?
Given
Inhaled air contains 21% oxygen while exhaled breath contains approximately 16% oxygen and 5% carbon dioxide
The minimum oxygen level required for survival is 19 %.
Dimensions of room in meters: 5 X 5 X 3
The acidity of water is a measure of the quantitative capacity to react with a mineral base. The measured value usually varies with the pH indicator used in the experiment. The solution of phenolphthalein is colourless in acidic or mild basic medium (pH<8.0), while in basic medium (pH<9.6) solution is pink. The solution of methyl orange is generally red at pH lower than 3.1 and above pH 4.4 the solutions are yellow.
The dissolved strong mineral acids, weak organic acids, dissolved carbon dioxide and hydrolyzed mineral salts may contribute to the measured acidity of natural water. The acidity of water is a significant parameter of water as the presence of acids in natural water contributes to corrosiveness and influences chemical reaction rates. The biological processes are dependent on the acidity of water. The quantitative acidity measurement also reflects the quality of the source of water. The acidity of water is usually expressed in terms of CaCO3.
Determine the strength in grams per litre of a given AgNO3 solution being pro...Mithil Fal Desai
Mohr’s method is used to determine the chloride ion concentration by titrating with silver nitrate. Using pure sodium chloride the strength of silver ions can be also determined as the Ag(I) ions react with chloride ions, quantitatively, to form a precipitate of silver chloride.
This is a small attempt to preserve heritage and folk culture of Goan village Adnem
Credits to Ghanashyam K. Devidas, Lakshimikant Bhavu, Vithobha Bhavu
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
5. Shielding
The reduction of the true nuclear charge to
effective nuclear charge by other electrons is
called shielding.
6. Energy of electron, atomic number,
principal quantum number
Energy of electron is a
function of Z2/n2
Does this mean that energy
required to remove
electron from an atom
continuously increases
with the atomic number?
Z n Z2/n2
1 1 1
2 1 4
3 2 2.25
4 2 4
5 2 6.25
6 2 9
7 2 12.25
8 2 16
9 2 20.25
7. Why this is not true?
A) Average radius of 2s
orbital is greater
than 1s.
A) 2s electrons are
repelled by 1s
electrons.
Nucleus
e-
8. Remember!
• Shielding and screening decreases the true nuclear
charge.
• Shielding constant can be measured following the
Slater rules
