Dmitri Ivanovich Mendeleev was a chemist known for developing the modern periodic table of elements.

How many elements were known to Mendeleev?

Around 63 elements were known to Mendeleev when he began his work.

Why did Mendeleev use hydrogen and oxygen for his experiments?

He used hydrogen and oxygen because they are very reactive, readily found, and form compounds with most elements.

What was Mendeleev's method for organizing elements?

He organized elements by their physical and chemical properties and arranged them in the increasing order of their atomic masses.

What did Mendeleev observe from arranging elements by atomic mass?

Mendeleev observed empty spaces for undiscovered elements and the recurrence of similar properties at periodic intervals.

What were Mendeleev's predictions about undiscovered elements?

He predicted the existence and properties of undiscovered elements, which were later found to be almost perfect matches.

What laid the foundation for the periodic table we use today?

Mendeleev's method of periodic classification and his periodic law laid the foundation for the modern periodic table.

Did Mendeleev's periodic table have any limitations?

Yes, Mendeleev's periodic table had some limitations, which emerged over time.

What will the next video discuss?

The achievements and limitations of Mendeleev's work.

Mendeleev’s Periodic Table | Classification of Elements | Don't Memorise

00:03:51

https://www.youtube.com/watch?v=0vIScP0aXN8

Summary

TLDRThe video discusses Dmitri Ivanovich Mendeleev's monumental contribution to chemistry, focusing on his development of the periodic table of elements. Mendeleev was determined to organize elements by their physical and chemical properties. He used hydrogen and oxygen due to their reactivity and ability to form compounds with most elements to help categorize these properties. Mendeleev wrote information about the elements on cards, arranging them by increasing atomic mass, leading to two significant observations: empty spaces predicted to be undiscovered elements with known properties, and the repetition of element properties at intervals, resulting in his formulation of the periodic law. This law posits that the properties of elements are periodic functions of their atomic masses. Mendeleev's periodic table served as the foundation for the modern periodic table but did have limitations that will be explored further in subsequent videos.

Takeaways

🎨 Mendeleev revolutionized chemistry with the periodic classification of elements.
💡 He arranged 63 known elements by chemical and physical properties.
🧪 Used hydrogen and oxygen to determine chemical properties due to their reactivity.
🗂 Created cards for each element to systematically organize them.
🔍 Predicted undiscovered elements and their properties accurately.
🔄 Observed recurring properties at intervals when elements were aligned by atomic mass.
📜 Established the periodic law which states periodic functions of properties related to atomic mass.
🧩 Found missing elements' slots in the table, hypothesizing their existence.
🗝 Laid the foundation for the modern periodic table we use today.
⏳ Limitations of this system unfolded with time, to be discussed in future content.

Timeline

00:00:00 - 00:03:51
Dmitri Ivanovich Mendeleev played a crucial role in chemistry by pioneering the periodic classification of elements. He identified a method to group elements based on their physical and chemical properties. To understand chemical properties, Mendeleev used reactions with hydrogen and oxygen due to their reactivity and ability to form compounds with most elements. He documented properties on 63 cards and arranged them by atomic mass, noticing two key patterns: empty spaces for undiscovered elements (which he accurately predicted) and recurring properties at regular intervals, leading to his formulation of the periodic law, stating properties are periodic functions of atomic masses. This laid the groundwork for the modern periodic table, though limitations became apparent over time, which will be explored further in another video.

Mind Map

Video Q&A

Who was Mendeleev?
Dmitri Ivanovich Mendeleev was a chemist known for developing the modern periodic table of elements.
How many elements were known to Mendeleev?
Around 63 elements were known to Mendeleev when he began his work.
Why did Mendeleev use hydrogen and oxygen for his experiments?
He used hydrogen and oxygen because they are very reactive, readily found, and form compounds with most elements.
What was Mendeleev's method for organizing elements?
He organized elements by their physical and chemical properties and arranged them in the increasing order of their atomic masses.
What did Mendeleev observe from arranging elements by atomic mass?
Mendeleev observed empty spaces for undiscovered elements and the recurrence of similar properties at periodic intervals.
What is the periodic law according to Mendeleev?
The periodic law states that the properties of elements are periodic functions of their atomic masses.
What were Mendeleev's predictions about undiscovered elements?
He predicted the existence and properties of undiscovered elements, which were later found to be almost perfect matches.
What laid the foundation for the periodic table we use today?
Mendeleev's method of periodic classification and his periodic law laid the foundation for the modern periodic table.
Did Mendeleev's periodic table have any limitations?
Yes, Mendeleev's periodic table had some limitations, which emerged over time.
What will the next video discuss?
The achievements and limitations of Mendeleev's work.

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Subtitles

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00:00:00
[Music]
00:00:04
Dmitri Ivanovich Mendeleev played quite
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a legendary role in the field of
00:00:09
chemistry he not only gave us the
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simplest and the most efficient method
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of grouping elements but also laid the
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foundations of periodic classification
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of elements that we used today so in
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this video let's dedicate some time to
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understand what and how Mendeleev
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actually worked on when Mendeleev began
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his work of grouping the elements and
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arranging them there were almost 63
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elements known to him he was firm on the
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thought of arranging the elements with
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respect to their physical as well as
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chemical properties he knew that for
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understanding the chemical properties he
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would need to make them react with one
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or two standard elements for this
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he chose hydrogen and oxygen but why
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Mendeleev thought of making the elements
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react with hydrogen and oxygen because
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of the following reasons
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they are very reactive they are found
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readily and they form compounds with
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most of the elements yes this helped him
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understand the chemical properties of
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all the reacting elements later in order
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to simplify the process he wrote all the
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physical and chemical properties of each
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element on 63 different cards now all he
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had to do is arrange these cards but
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that wasn't so simple so he started
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arranging the cards in the increasing
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order of the atomic masses when he was
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done pasting all these cards on his wall
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he had two astonishing observations one
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was that there were a few empty spaces
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left in the complete table that he
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formed these positions belong to the
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elements that would not yet discovered
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but Mendeleev had a firm belief that the
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missing elements did exist and are yet
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to be discovered not only this but he
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was so confident about the
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characteristics of these elements that
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he predicted their properties well in
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advance later on when the elements were
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discovered it was found that the
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property is predicted by Mendeleev for
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almost a
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perfect match second observation that
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Mendeleev had was the recurrence of the
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physical and chemical properties of
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these elements when arranged in a
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systematic manner it was found that the
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physical and chemical properties of
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elements record at a particular interval
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of frequency with this Mendeleev came up
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with a law he named it as the periodic
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law the law stated that properties of
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elements are periodic functions of the
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atomic masses now what do we exactly
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mean by this let's simplify this by
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breaking the statement in parts
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properties of elements means the
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physical and chemical properties of all
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the elements in the table are the
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periodic functions means those which
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occur at regular intervals and lastly of
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the atomic masses means when arranged in
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the increasing order of the atomic
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masses so can we simply say that when
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elements are arranged in the increasing
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order of the atomic masses they show
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similarities in the physical and
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chemical properties at regular intervals
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yes that's what Mendeleev meant this is
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how Mendeleev let the foundations for
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the modern periodic table but did this
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great contribution by Mendeleev have no
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limitations at all well there were a few
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that emerged with time let's discuss the
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achievements and the limitations of
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Mendeleev's work in the next video
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[Music]
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you