Answer:
Lavoisier; Newlands; Moseley
Explanation:
In 1789, Antoine Lavoisier grouped the elements into gases, nonmetals, metals, and earths.
In 1865, John Newlands developed the Law of Octaves. He stated that "any given element will exhibit analogous behaviour to the eighth element following it in the table."
In 1914, Henry Moseley found a correlation between the X-ray wavelength of an element and its atomic number. He was then able to restructure the periodic table according to atomic numbers.
Answer:
Acetic acid , systematically named ethanoic acid , is a colourless liquid organic compound with the chemical formula CH3COOH.
Explanation:
<span>The symbol for the element whose atoms have 40 electrons each is Zr. This is the element zirconium. In the atoms of a pure element, the number of positively charged protons is normally equal to the number of negatively charged electrons. Hence, the number of electrons in the atom can be inferred from the atomic number, which corresponds to the number of protons in an atom. The atomic number of zirconium is 40.</span>
Answer:
B .it is an exothermic reaction
Explanation:
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