History of Periodic Table Animation

00:06:38
https://www.youtube.com/watch?v=ogpWoB4m-Ns

Summary

TLDRThe video outlines the evolution of the periodic table, starting with early classification efforts by Johann Wolfgang Döbereiner, who grouped elements into triads based on similar properties. This effort was followed by Newlands, who arranged elements by increasing atomic mass and noted a pattern every eighth element, akin to musical octaves, though he faced limitations when new elements didn't fit this scheme. Dmitri Mendeleev made significant advances by arranging elements according to atomic mass and predicted undiscovered elements. His table had horizontal periods and vertical groups. Mendeleev’s system had drawbacks, such as the incorrect positioning of hydrogen and placing some elements in the same subgroup despite differing properties, prompting the need for improved systems. The modern concept of arranging elements by atomic number, proposed by Henry Moseley, overcame these issues. This led to the modern periodic law, which became the foundation of the current periodic table widely used today, accurately reflecting elements' chemical and physical properties.

Takeaways

  • 🧪 Döbereiner's triads classified elements in groups of three based on similar properties.
  • 🎶 Newlands' Law of Octaves noted a pattern every eighth element but had limitations.
  • 🔬 Mendeleev arranged elements by atomic mass and predicted undiscovered elements.
  • 📅 Mendeleev's table introduced the concepts of periods and groups.
  • ❌ Mendeleev faced challenges with element positioning, especially hydrogen.
  • 🔢 Moseley discovered that atomic number is fundamental to element classification.
  • 📊 The modern periodic law uses atomic numbers, not atomic masses, for categorization.
  • 🔍 Modern periodic tables more accurately reflect elements' properties than previous versions.
  • ⚡ Changes in classification methods were driven by new discoveries and inconsistencies.
  • 🔻 Noble gases were seamlessly added to Mendeleev’s table, highlighting its robustness.

Timeline

  • 00:00:00 - 00:06:38

    The video discusses the classification of elements into elements, compounds, and mixtures, starting with Johann Wolfgang Döbereiner, who discovered groups of three elements with similar properties, called triads. However, Döbereiner's method had limitations as not all elements fit into these groups. The second attempt was by John Newlands, who arranged 56 known elements by increasing atomic mass and observed that every eighth element had similar properties. He related this to octaves in music, known as Newlands' Law of Octaves. However, his classification was limited as it only worked up to calcium. Mendeleev later developed the periodic table ordered by atomic masses, predicting undiscovered elements, but it had shortcomings, such as unclear placement for hydrogen and inconsistencies with other elements. Henry Moseley later determined atomic number as the fundamental property, leading to the modern periodic table based on atomic numbers, known as the Modern Periodic Table.

Mind Map

Video Q&A

  • Who was the first to attempt classifying elements?

    Johann Wolfgang Döbereiner was the first to classify elements in 1829.

  • What was Newlands' contribution to element classification?

    Newlands arranged elements by increasing atomic mass and noted every eighth element had similar properties, a concept known as Newlands' Law of Octaves.

  • What is Mendeleev's periodic law?

    It states that the physical and chemical properties of elements are a periodic function of their atomic masses.

  • What were the limitations of Mendeleev's periodic table?

    Mendeleev could not place hydrogen properly, had elements with higher atomic masses before those with lower, and grouped elements with different properties together.

  • What significant change did Henry Moseley introduce?

    Henry Moseley identified atomic number as the key property for classifying elements, leading to the modern periodic law.

  • How did noble gases fit into Mendeleev’s table?

    Noble gases were added to Mendeleev's table without disrupting the order of existing elements.

  • What does the modern periodic law state?

    The modern periodic law states that the properties of elements are a periodic function of their atomic numbers.

  • What are groups and periods in a periodic table?

    Groups are columns numbered 1 to 8, and periods are horizontal rows in the periodic table.

  • How many elements were included in Mendeleev's first periodic table?

    Mendeleev's initial periodic table included 63 known elements.

  • What was the significance of blank spaces in Mendeleev's table?

    The blank spaces were for undiscovered elements whose properties Mendeleev predicted accurately.

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  • 00:00:02
    [Music]
  • 00:00:10
    we all know that matter can exist in the
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    form of elements compounds and mixture
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    when elements were discovered a brothel
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    classification was required for the
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    easier and better understanding many
  • 00:00:28
    scientists adopted different ways to
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    classify them they tried to find out
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    some pattern or regularity and
  • 00:00:38
    properties of elements the first among
  • 00:00:42
    them was Johann Wolfgang Toto Riina
  • 00:00:46
    a journal scientist who in 1829 found
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    some groups of three elements which
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    showed similar properties these groups
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    gold has trouble Reiner trial here if we
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    have a look I try a table we can see
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    that the atomic mass the middle element
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    is approximately the main of the atomic
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    masses of the other two elements as this
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    classification was a primitive step
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    dauber IRA could identify only some
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    trials from the elements no
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    other tribes did not obey the rule and
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    the system of tribe was not useful after
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    the failure of doe Barinas drive the
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    next attempt to classify elements was
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    done by British chemist Newlin - time 56
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    elements were discovered he arranged all
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    these elements in an increasing order of
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    atomic masses and found that every
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    eighth element and properties similar to
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    that of the first
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    he compared this to the Optus found in
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    music and therefore this classification
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    was known as Newlands octane however
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    this classification had his own share or
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    shortcoming the main point being that
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    Nuland could arrange elements only up to
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    calcium out of the total 56 elements no
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    after which the elements did not show
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    similar properties also later several
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    new elements which did not feature in
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    humans classification were discovered
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    after the period of Newlands obtained
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    the Madrid ivanovitch Mendeleev Russian
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    chemist put forward a periodic table
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    that was called Mendeleev periodic table
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    mentally examined the relationship
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    between the atomic masses of the
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    elements and the physical and chemical
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    properties
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    he believed that atomic mass with
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    element was the most fundamental
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    property and classifying the element he
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    arranged the known elements in the
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    increasing order of their atomic masses
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    and the properties and thus created the
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    first periodic table containing 63
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    elements until then known as Mendeleev
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    periodic table Mendeleev law states that
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    the physical and chemical properties of
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    elements or a periodic function of their
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    atomic masses in the mentally sporadic
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    tables the horizontal rows in the
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    periodic table
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    are called easier there are in total
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    seven period the vertical columns in the
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    periodic table are called
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    group there are eight groups numbered
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    from 1 to 8
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    Mendeleev get some blank spaces in this
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    periodic table the vacant spaces were
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    four elements have we yet to be
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    discovered he named them I can't go
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    wrong a cog
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    aluminium and account silicon and also
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    predicted the property which later were
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    found to be correct when noble gases
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    were discovered they were placed the
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    Mendeleev table without disturbing the
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    position of other enemies the Mendeleev
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    periodic table however had its own
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    demerit firstly no fixed position could
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    be given to hydrogen in the table as it
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    resembled alkali metals as well as
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    halogen at certain places an element of
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    piled atomic mass has been placed before
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    an element of lomar there is more
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    example
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    cobalt whose atomic mass is fifty eight
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    point nine three is placed before nickel
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    force atomic mass is fifty eight point
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    seven one also some elements place the
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    same subgroup at different properties
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    example manganese and M is placed with
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    halogens which don't lead the fall in
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    property due to these irregularities the
  • 00:05:32
    need for a new classification GaAs
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    emerged
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    in 1913 Henry Moseley and English
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    physicist discovered that atomic number
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    is the most fundamental property of an
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    element and not the atomic mass this
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    discovery changed the whole perspective
  • 00:05:52
    of elements and their properties
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    accordingly
  • 00:05:57
    Mendeleev periodic law was modified into
  • 00:06:00
    modern periodic law which states that
  • 00:06:03
    the chemical and physical properties of
  • 00:06:06
    elements of a periodic function
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    Oster atomic number the periodic table
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    based on modern periodic law is called
  • 00:06:15
    modern periodic table many versions of
  • 00:06:19
    this periodic table are in use but the
  • 00:06:23
    one which is most commonly used is long
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    formed of modern periodic table we shall
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    now learn in detail about the modern
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    periodic table
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    [Music]
Tags
  • Periodic Table
  • Elements
  • Classification
  • Chemistry
  • Mendeleev
  • Atomic Mass
  • Atomic Number
  • Chemical Properties
  • Newlands Octaves
  • Modern Periodic Law