Dmitri Ivanovich Mendeleev, a Russian scientist arranged the elements in increasing order of their relative atomic masses. He was honoured with Noble prize in 1906 for his Periodic Table.

 

Mendeleev’s Periodic Law states that the properties of elements are the periodic function of their relative atomic masses.

 

Mendeleev arranged all 63 elements; which were discovered till his time; in the order of their increasing relative atomic masses in a tabular form. It is known as Mendeleev’s Periodic Table. He divided the table in eight columns and seven rows. The columns are known as groups and rows are known as periods.

It is the arrangement of elements done by Newland in which 8 elements were arranged in such a way that every 8th element has properties same as the first one.

 BOOK FREE CLASS COMPETITIVE EXAMS BNAT Classes CBSE NCERT Solutions Commerce ICSE IAS JEE NEET State Boards Government Exams Kids Learning Academic Questions Online Tuition Full Forms CAT BUY A COURSE +919243500460 Chemistry Chemistry Articles Periodic Table Named Reactions Chemistry Laws Chemistry Important Questions Chemistry Classification of Elements and Periodicity in Properties Newlands Law Of Octaves  Newland’s Law of Octaves and Dobereiner’s Triads Dobereiner’s triads and Newland’s law of octaves were early attempts at classifying elements into groups based on their properties. Since many new elements were discovered over the course of the 18th and 19th centuries, the broad classification of elements into metals and non-metals became inefficient. Several experiments were conducted in order to identify elements with similar properties and group them together. It is important to note that the primitive methods of classifying elements, such as Newland’s law of octaves and Dobereiner’s triads, laid the foundation for the development of the modern periodic table. What are Dobereiner’s Triads? Dobereiner’s triads were groups of elements with similar properties that were identified by the German chemist Johann Wolfgang Dobereiner. He observed that groups of three elements (triads) could be formed in which all the elements shared similar physical and chemical properties. Dobereiner stated in his law of triads that the arithmetic mean of the atomic masses of the first and third element in a triad would be approximately equal to the atomic mass of the second element in that triad. He also suggested that this law could be extended for other quantifiable properties of elements, such as density. The first of Dobereiner’s triads was identified in the year 1817 and was constituted by the alkaline earth metals calcium, strontium, and barium. Three more triads were identified by the year 1829. These triads are tabulated below. Triad 1 This triad was made up of the alkali metals lithium, sodium, and potassium. TriadAtomic MassesLithium6.94Sodium22.99Potassium39.1 The arithmetic mean of the masses of potassium and lithium corresponds to 23.02, which is almost equal to the atomic mass of sodium. Triad 2 As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads. TriadAtomic MassesCalcium40.1Strontium87.6Barium137.3 The mean of the masses of barium and calcium corresponds to 88.7. Triad 3 The halogens chlorine, bromine, and iodine constituted one of the triads. TriadAtomic MassesChlorine35.4Bromine79.9Iodine126.9 The mean value of the atomic masses of chlorine and iodine is 81.1. Triad 4 The fourth triad was formed by the elements sulfur, selenium, and tellurium. TriadAtomic MassesSulfur32.1Selenium78.9Tellurium127.6 The arithmetic mean of the masses of the first and third elements in this triad corresponds to 79.85. Triad 5 Iron, cobalt, and nickel constituted the last of Dobereiner’s triads. TriadAtomic MassesIron55.8Cobalt58.9Nickel58.7 However, the mean of the atomic masses of iron and nickel corresponds to 57.3. Limitations of Dobereiner’s Triads The key shortcomings of Dobereiner’s method of classifying elements are listed below. The identification of new elements made this model obsolete. Newly discovered elements did not fit into the triads. Only a total of 5 Dobereiner’s triads were identified. Even several known elements did not fit into any of the triads. Owing to these shortcomings, other methods of classifying elements were developed. Newland’s Law of Octaves In the year 1864, the British chemist John Newlands attempted the 62 elements known at that time. He arranged them in an ascending order based on their atomic masses and observed that every 8th element had similar properties. On the basis of this observation, Newland’s law of octaves was formulated. The law of octaves states that every eighth element has similar properties when the elements are arranged in the increasing order of their atomic masses. An illustration detailing the elements holding similar properties as per Newland’s law of octaves is provided below.  Newlands compared the similarity between the elements to the octaves of music, where every eighth note is comparable to the first. This was the first attempt at assigning an atomic number to each element. However, this method of classifying elements was met with a lot of resistance in the scientific community. Limitations of Newland’s Law of Octaves The key shortcomings of Newland’s law of octaves are listed below. Several elements were fit into the same slots in Newland’s periodic classification. For example, cobalt and nickel were placed in the same slot. Elements with dissimilar properties were grouped together. For example, the halogens were grouped with some metals such as cobalt, nickel, and platinum. Newland’s law of octaves held true only for elements up to calcium. Elements with greater atomic masses could not be accommodated into octaves. The elements that were discovered later could not be fit into the octave pattern. Therefore, this method of classifying elements did not leave any room for the discovery of new elements. To learn more about Newland’s law of octaves and Dobereiner’s Triads along with other related concepts, such as Mendeleev’s periodic table, register with BYJU’S and download the mobile application on your smartphone. 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In the year 1864, the British chemist John Newlands attempted the 62 elements known at that time. He arranged them in an ascending order based on their atomic masses and observed that every 8th element had similar properties. On the basis of this observation, Newland’s law of octaves was formulated.

The law of octaves states that every eighth element has similar properties when the elements are arranged in the increasing order of their atomic masses.

Newlands compared the similarity between the elements to the octaves of music, where every eighth note is comparable to the first. This was the first attempt at assigning an atomic<a href="https://byjus.com/chemistry/atomic-number-mass-number/"> </a>number to each element. However, this method of classifying elements was met with a lot of resistance in the scientific community

Hii

1. Liberalisation of law 2. Trade barriers finished at the national and international level 3. Improve in Foreign direct investment 4. Fair rules and regulations will be issued by WTO(world trade organisations)

Reduction of barrier ? policies in favour of trade

Reduction of barrier ? policies in favour of tradw

Ans

 

The French Revolutionwas a revolution inFrance from 1789 to 1799. The French Revolution led to the end of the monarchy, and to many wars. King Louis XVI was executed in 1793.

 

 

CAUSES

The financial strain of servicing old debt and the excesses of the current royal court caused dissatisfaction with the monarchy, contributed to national unrest, and culminated in the French Revolution of 1789.

 

 

 

GOALS OF THIS REVOLUTION

 

The goal was to change the system, and get food back into citizens' mouths. The goal was to get rid of the monarchy and found a system powered by the people. The main goal of the French Revolution was, obviously, to overthrow the French monarchy.

 

 

 

 

PURPOSE

When the French Revolutionbroke out in 1789, its main purpose was to address the financial problems of the regime. The numerous wars of the eighteenth century in which France was involved, e.g. the French and Indian War, had caused the government to spend more than it received in revenue.

 

Try to understand not to remember

Use learning acronyms or tricks.. And play study music in the background

Study with CONCENTRATION and INTEREST

Mujhe bhi nahi ati?

calm down

Kehna Kya Chahte Ho??

????? .., Life 3.0: Being Human in the Age of Artificial Intelligence is a book by Swedish-American cosmologist Max Tegmark from MIT. Life 3.0 discusses Artificial Intelligence and its impact on the future of life on Earth and beyond.

what????????

??

What?

Tankd

Dmitri Ivanovich Mendeleev, a Russian scientist arranged the elements in increasing order of their relative atomic masses. He was honoured with Noble prize in 1906 for his Periodic Table.

Mendeleev’s Periodic Law states that the properties of elements are the periodic function of their relative atomic masses.

Mendeleev arranged all 63 elements; which were discovered till his time; in the order of their increasing relative atomic masses in a tabular form. It is known as Mendeleev’s Periodic Table. He divided the table in eight columns and seven rows. The columns are known as groups and rows are known as periods.

• Elements are arranged in the periodic table in the increasing order of their relative atomic masses.
• Mendeleev divided his periodic table in eight groups and seven periods.
• Groups from I to VII are meant for normal elements and group VIII is for transition elements.
• Groups from I to VII have been divided in two sub groups, while group VIII is meant for three elements.
• Periods from 4th to 7th have been divided in two series: 1st series and 2nd series.
• Elements having similar properties have been kept in the same group. For example; lithium, potassium, rubidium, etc. are in 1st group.

P= w/q I= q/ t Ohms law v= R×i Parallel R= 1/R1 ×1\R2 Series R = R× R.

1) I=q/t 2)V=W/Q 3) V=IR 4) R= pl/ A 5) Rs= R1+R2+R3 6) 1/Rp= 1/ R1+ 1/ R2 + 1/ R3 7) H = I2Rt 8) P= W/t 9) P= VI 10) P = V2/ R

Fossil fuels are the fuels formed by natural processes such as decomposition of dead and buried organisms.

Fossil fuels are buried flammable geologic deposits of organic substances such as dead plants, and animals that got deposited under several thousand feet of silt. These deposits decayed with the passage of time and got converted to natural gas, coal, and petroleum due to the extreme heat and pressure inside the earth’s crust. They are also known as non-renewable sources of energy as it takes a very long time for it to replenish.

Right

15m+3n=6 ..... (i)

6m+3n=1..... (ii)

Subtract (i) and (ii)

     15m + 3n = 6

-     6m + 3n=1

-------------------

9m = 5

m = 5/9

Put m = 5/9 in  (ii), we get

6m + 3n = 1

6(5/9) + 3n = 1

10/3 + 3n = 1

3n = 1 - 10/3

3n = (3 - 10)/3

3n = -7/3

n = -7/9

Can you guys explain how you have calculated. I am feeling as I have not studied that chapter thoroughly.

10 J of energy is available to the deer to transfer it to the lion.

By 10% law 1000J of energy is available in plant and 100J is available in lion.

9m

9m

The alimentary canal in human beings extends from mouth to ****. In human beings, it measures about 8 to 10 meters in length. Gastro-intestinal tract can be divided into upper tract and lower tract.

Alimentary canal is the long tube of organs and it is about 8.6 to 8.9m long.

The Salt March was an effective symbol of resistance against colonialism because it was done in revolt against a commodity—salt, used by the rich and the poor alike. The tax on salt, and the government monopoly over its production was a severely oppressive administrative move. The Salt March was effective also because Gandhiji met a large number of commoners during the march and he taught them the true meaning of swaraj and non-violence. By peacefully defying a law and making salt against government orders, Gandhiji set forth an example to the whole nation of how the oppressor could be confronted in a non-violent manner. This also led to the Civil Disobedience Movement in 1930.

The Salt March was an effective symbol of resistance against colonialism because it was done in revolt against a commodity—salt, used by the rich and the poor alike. The tax on salt, and the government monopoly over its production was a severely oppressive administrative move.

ह्यः त्वम कुत्र आसीः?

What a question

 F-114 Mall Road 

Agra 

24 July 20 XX 

The Editor 

The Hindu Agra 

Subject : Increasing Dependence on Coaching Institutions 

Sir 

Through the columns of your reputed newspaper I wish to draw the attention of the general public towards the increasing dependence of students on the coaching institutes. It has generally been observed that students rely more on coaching institutions than on schools. The reason behind this is that these centres are easily accessible and more practice-based. On the other hand, schools prepare students only for the Board Exams and not for the entrance exams. 

This trend can be checked by ensuring that teaching in the school classroom is not just limited to board-oriented syllabus. They must prepare students for competitive exams also. Schools must provide more practice-material to the students. The environment of the classroom should be such that the students get interested in studies.

Teachers should pay attention to the individual problems. 

I hope you will publish this letter in your newspaper so that the concerned authorities become aware of their shortcomings and do the needful. 

Thanking you 

Yours sincerely 

Arun

Reproduction at its most basic level involves making copies of the blueprints of body design. During reproduction, the information for inheritance of characteristics is passed on from the parents to the offsprings in the form of DNA. DNA in the cell nucleus is the information. Hence DNA copying is the basic event in reproduction.

Clergyman Burgled: A strange episode occurred. A clergyman and his wife were awakened by the noises in the study very early in the morning. They came downstairs and heard the chink of money being taken from the desk. ... and the money was missing.Answer: Explanation:Both Mr and Mrs Bunting heard the chink of money and realised that the robber must have found the house keeping reserve of gold. When they went inside, they could not see anyone but heard a violent sneeze in the passage.

Clergyman Burgled: A strange episode occurred. A clergyman and his wife were awakened by the noises in the study very early in the morning. They came downstairs and heard the chink of money being taken from the desk. With poker in his hand, the clergyman flung open the door. He shouted, “surrender!” He was surprised to see the room empty. They looked under the desk, behind d the curtains and even up the chimney. one was there. They found the desk open. and the money was missing. They were highly surprised, couldn’t understand anything.

If magnetic field lines intersect each other, then at the intersection point there will be two directions of the same field which is not possible. Hence the field lines do not cross or intersect each other.

Answer:

Magnetic lines of force are defined as the curved lines which are used for representing the magnetic field. These lines do not exist but are imaginary lines through the pattern of the magnetic field is explained. These imaginary lines are assumed to originate from the north pole and reach to the south pole by travelling inside the magnet thereby completing the loop.

Properties of magnetic lines of force

• Magnetic field lines originate from the north pole and merge at the south pole.
• As the distance between the poles tends to increase, magnetic line density reduces.
• Inside the magnet, the position of the field lines is from the South Pole to the North Pole.
• Magnetic lines do not intersect with one another.
• The magnetic lines strength is the same throughout, and it is proportional to how near the lines are.

 

Reason – The two magnetic field lines do not intersect each other because if they do it means at the point of intersecting the compass needle is showing two different directions which are not possible.

Cos theta =B/H

Cos theta = Sin(90°- theta)

Cos theta = Sin(90°- theta)

Cos theta = 1/Sec theta

Cos thita = 1/sec thita

Potential difference: potential difference between two point that is called potential difference.... Insulator: A substance in which current doesn't flow is called insulator... Conductor:. A substance in which current flow is called conductor....

In a conductor, electrons flow only when there is a difference in electric pressure at its ends. This is also called potential difference. In a circuit, this potential difference is created by a battery.

Electrical conductor:An electrical conductor is a substance that allows an electrical current to pass through it. Electrical conductors are usually metals. Copper is one of the best electrical conductors, and this is why it is used to make conducting wire.

Insulators: An insulator is a non-conducting material that does not carry any charge.Examples of insulators are plastic and wood.

Let AB be the vertical pole and CA be the rope. Then,

∠ACB=30^o and AC=20 m

In right △ ABC,

sin30^o = AB​/AC

1/2 ​=AB​/20

AB=10 m

Therefore, the height of the pole is 10 m.

(1) Federalism is the system of government in which sovereignty is constitutionally divided between a central governing authority and constituent political units.

(2) The Federal Government is composed of three distinct branches: legislative, executive, and judicial.

(3) These three braches are vested by the U.S. Constitution in the Congress, the President, and the Federal courts, respectively.

(4) Each branch has its own powers and responsibilities.

(5) In India, a Sovereign Socialist Secular Democratic Republic with a Parliamentary House, organize the federal structure.

(6) Hence, federal government is organised when their is a sharing of power between national and state governments.

A type of development in which we use resources to satisfy the need of present generation and protect for coming generation without harming the environment

Sustainable development is the practice of using guidelines for environmentally responsible and energy savings to create new development projects and to maintain and retrofit older projects. It can include using green materials in new construction, designing projects that can harvest their own energy to reduce the load on a power grid, or that incorporate green space in order to counterbalance the green space removed to build the onsite facilities. There is a heavy emphasis on making sure that what is built can be maintained and repaired in a way that minimizes the degradation of the original development so that the lifespan of a facility is longer than normal.

Take help from given link:

<a href="https://www.conserve-energy-future.com/what-is-sustainable-development-and-its-goals.php#:~:text=Sustainable%20development%20is%20the%20practice,maintain%20and%20retrofit%20older%20projects." ping="/url?sa=t&source=web&rct=j&url=https://www.conserve-energy-future.com/what-is-sustainable-development-and-its-goals.php%23:~:text%3DSustainable%2520development%2520is%2520the%2520practice,maintain%2520and%2520retrofit%2520older%2520projects.&ved=2ahUKEwjvscSE2-_sAhWSzDgGHf97A1MQFjABegQIBRAC" rel="noopener" target="_blank">What is Sustainable Development: Goals, Importance and ...</a>

Coordinate geometry deals with graphing (or plotting) and analyzing points, lines, and areas on the coordinate plane (coordinate graph). Each point on a number line is assigned a number. In the same way, each point in a plane is assigned a pair of numbers.