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    Green Gradient Monotone Minimalist Presentation Template - 20240206 - 220317 - 0000

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    John Dalton was an English chemist born in 1766 who developed atomic theory. Through experiments with gases, Dalton observed that elements combine in fixed ratios by mass and proposed that all matter is made of tiny indivisible particles called atoms. His atomic theory stated that atoms of a given element are identical, atoms cannot be created or destroyed, and atoms of different elements have different properties and combine to form compounds in simple whole number ratios. While Dalton's theory was groundbreaking, later discoveries of subatomic particles disproved some of his ideas like atoms being indivisible.

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    Green Gradient Monotone Minimalist Presentation Template - 20240206 - 220317 - 0000

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    25 views13 pages
    John Dalton was an English chemist born in 1766 who developed atomic theory. Through experiments with gases, Dalton observed that elements combine in fixed ratios by mass and proposed that all matter is made of tiny indivisible particles called atoms. His atomic theory stated that atoms of a given element are identical, atoms cannot be created or destroyed, and atoms of different elements have different properties and combine to form compounds in simple whole number ratios. While Dalton's theory was groundbreaking, later discoveries of subatomic particles disproved some of his ideas like atoms being indivisible.

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    Green Gradient Monotone Minimalist Presentation Template_20240206_220317_0000

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    John Dalton was an English chemist born in 1766 who developed atomic theory. Through experiments with gases, Dalton observed that elements combine in fixed ratios by mass and proposed that all matter is made of tiny indivisible particles called atoms. His atomic theory stated that atoms of a given element are identical, atoms cannot be created or destroyed, and atoms of different elements have different properties and combine to form compounds in simple whole number ratios. While Dalton's theory was groundbreaking, later discoveries of subatomic particles disproved some of his ideas like atoms being indivisible.

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    25 views13 pages

    Green Gradient Monotone Minimalist Presentation Template - 20240206 - 220317 - 0000

    Uploaded by

    harukii.ft.eya
    John Dalton was an English chemist born in 1766 who developed atomic theory. Through experiments with gases, Dalton observed that elements combine in fixed ratios by mass and proposed that all matter is made of tiny indivisible particles called atoms. His atomic theory stated that atoms of a given element are identical, atoms cannot be created or destroyed, and atoms of different elements have different properties and combine to form compounds in simple whole number ratios. While Dalton's theory was groundbreaking, later discoveries of subatomic particles disproved some of his ideas like atoms being indivisible.

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    of 13

    John

    D a l t o n ’ s
    Atomic Theory
    The atomic theory was a philosophical speculation that all things can
    be accounted for by innumerable combinations of hard, small,
    indivisible particles (called atoms) of various sizes but of the same
    primary material; or the modern scientific theory of matter according
    to which the chemical elements that combine to form the great
    variety of substances consist themselves of aggregations of similar
    subunits (atoms) possessing nuclear and electron substructure
    characteristic of each element. The ancient atomic theory was
    proposed in the 5th century BCE by the Greek philosophers Leucippus
    and Democritus. It was revived in the 1st century BCE by the Roman
    philosopher and poet Lucretius. The modern atomic theory, which has
    undergone continuous refinement, began to flourish at the beginning
    of the 19th century with the work of the English chemist John Dalton.
    John Dalton
    Was an English chemist, physicist and influential scientist of the
    eighteenth and nineteenth centuries, John Dalton was born into a
    Quaker family on September 5 or 6, 1766, in Eaglesfield, Cumberland,
    England and died on July 27, 1844 Manchester England . The members
    of the Dalton family were tradesmen, but his mother came from a
    wealthy family. John was the youngest of the three surviving ch po
    ildren, and he attended a Quaker grammar school. At the age of
    twelve, John's older brother took over the school and often asked
    John to assist in teaching.
    Furthermore
    In 1793, John Dalton joined the faculty of the Manchester Academy, The New
    College, as a mathematics instructor. During that time, he also published his
    work Meteorological Observations and Essays. Through the duration of his
    early research years, Dalton proposed many ideas such as that of the
    atmosphere being composed of a mixture of gases. He also studied color
    blindness and the atomic masses of atoms. The atomic mass research later
    led to several scientific laws and theories.

    In his fifties, John Dalton was awarded an honorary doctorate from Oxford,
    was elected into the fellowship of the Royal Society of London and became
    one of eight members of the French Academy of Sciences.
    Dalton’s
    Atomic Theory
    Dalton's study of gases, their atomic
    masses, and their tendency to
    combine atoms in small, whole-
    number ratios of fixed mass led to the
    development of Dalton's Atomic
    Theory, most of which holds true
    today.
    Atomic Theory
    Dalton’s atomic theory was a scientific theory on the nature of matter in the year 1803. It stated that
    all matter was made up of small, indivisible particles known as ‘atoms’. It was the first complete
    attempt to describe all matter in terms of atoms and their properties.

    Dalton based his theory on two laws: the law of conservation of mass and the law of constant
    composition.
    The law of conservation of mass says that matter is not created or destroyed in a closed system.
    That means if we have a chemical reaction, the amount of each element must be the same in the
    starting materials and the products. The law of constant composition says that a pure compound will
    always have the same proportion of the same elements.

    The postulates of Dalton's theory were:


    - All matter is made up of tiny, indivisible particles called atoms.
    - All atoms of a specific element are identical in mass, size, and other properties. However, atoms of
    different elements exhibit different properties and vary in mass and size.
    - Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller
    particles.
    - Atoms of different elements can combine with each other in fixed whole-number ratios in order to
    form compounds.
    - Atoms can be rearranged, combined, or separated in chemical reactions.
    Atomic Theory
    Although, there were some limitations to Dalton's Theory.

    It does not account for subatomic particles. Dalton’s atomic theory stated that atoms
    were indivisible. However, the discovery of subatomic particles (such as protons, electrons,
    and neutrons) disproved this postulate. It does not account for isotopes. As per Dalton’s
    atomic theory, all atoms of an element have identical masses and densities. However,
    different isotopes of elements have different atomic masses (For example: hydrogen,
    deuterium, and tritium). It does not account for isobars: This theory states that the masses
    of the atoms of two different elements must differ. However, it is possible for two different
    elements to share the same mass number. Such atoms are called isobars. Elements need
    not combine in simple, whole-number ratios to form compounds. Certain complex organic
    compounds do not feature simple ratios of constituent atoms. Example: sugar/sucrose.
    The theory does not account for allotropes. The differences in the properties of diamond
    and graphite, both of which contain only carbon, cannot be explained by Dalton’s atomic
    theory.
    How?
    Due to his interest and fascination in gases and how they interact with each other, John
    Dalton created a study that examined the properties of atmospheric gases.

    This study was conducted in 1803 and it involved the combination of oxygen with one-
    two volumes of nitric oxide contained in closed vessels over water. This study showed
    that oxygen interacted with either one or two volumes of nitric oxide, this was an
    observation of integral multiple proportions. Although it is to be noted that future
    attempts to recreate this study have been unsuccessful which leads some people to
    believe that these results were fraudulent.

    John Dalton stated that when two elements combine with each other to form two or
    more compounds, the ratios of the masses of one element that combines with the fixed
    mass of the other are whole numbers. This is now called John Dalton's law of integral
    multiple proportions and it served as a basis for his atomic theory and how atoms not
    only make up matter, but how they interact with each other as well.
    Why was it
    rejected?
    John Dalton proposed his theory on 1808. It is not the
    same for Rutherford's atomic theory for subatomic
    particles: Dalton's atomic theory stated that atoms
    were indivisible. However, the discovery of subatomic
    particles (such as protons, electrons, and neutrons)
    disproved this postulate.. Thereforre another model of
    an atom was made
    I t s t i m e
    t o a s k !
    Atomic Theory
    e f e r e n c e s :
    R
    https://www.khanacademy.org/science/chemistry/electronic-structure-of-
    atoms/history-of-atomic-structure/a/daltons-atomic-theory-version-2

    https://www.britannica.com/biography/John-
    Dalton/Atomic-theory

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