Organized the 33 known elements into four groups:

• Metals

• Nonmetals

• Gases

• Earths

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Antoine Lavoisier (1743–1794)

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​allowed scientists to break compounds down into simpler elements.

Discovery of Electricity​

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allowed scientists to identify individual elements.

Invention of Spectrometer​

many chemical industries developed new compounds such as fertilizers and dyes

Industrial Revolution​

Scientists found a method of measuring an elements atomic mass​

​Atomic mass

arranged 14 of the known elements according to increasing atomic mass.

• Newlands discovered that the properties of elements are repeated every eighth element.

• He called this relationship as the law of octaves.

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​The law of octaves did not apply to all elements

​John Newlands (1837–1898)​

​Arranged the elements in the order of atomic mass.

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He was the first to show connection between the atomic mass and the properties of elements

​He didn't publish first

​Lother Mayer

-Arranged the elements in the order of atomic mass.

-Showed the connection between atomic mass and properties of elements

-Left empty spaces for undiscovered elements​

-Predicted the properties of undiscovered elements​

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​He placed some of the elements in the worng position due to unaccuracy of atomic masses.

Dmitri Mendeleev

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-Said every element has a unique number called atomic number which means the number of protons in an atom.

​-Arranged the elements in the order of atomic number.

-Corrected the errors in Mendeleev's table.

-​Element's properties repeated in a periodic pattern.

​Some text here about the topic of discussion.

​Henry Moseley

States that when elements are arranged in order of atomic number, the properties of elements are repeated at regular intervals

Periodic law