(a) Why do we classify elements? (b) What were the two criteria used by Mendeleev in creating his Periodic Table? ... Justify your answer. -Chemistry 9th

(a) Why do we classify elements? (b) What were the two criteria used by Mendeleev in creating his Periodic Table? ... Justify your answer. -Chemistry 9th
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1 Answer

Answer :

(a) It is done so as to study the properties of elements conveniently. (b) Increasing order of atomic mass and similarities in chemical properties (especially nature and formulae of oxide and hydride formed). (c) These gaps were left for undiscovered elements. (d) Noble gases were not invented at that time. (e) They will be kept at same slot as they have same chemical properties.
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Related questions

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Description : Find the mass of 1.5 mole of CO2 molecule -Chemistry 9th

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Description : Find the number of atoms in 0.5 mole of C atom. -Chemistry 9th

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Description : What is the difference between molecules 2O and O2? -Chemistry 9th

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Description : Calculate the formula unit mass of NaCl and CaCl2. -Chemistry 9th

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Description : What is the difference between cation and anion? -Chemistry 9th

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Description : Define the term valency. What is the valency for magnesium and copper? -Chemistry 9th

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Description : Find the molecular mass of H2O. -Chemistry 9th

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What is an ion? Explain the types of ion with examples. -Chemistry 9th

Description : What is an ion? Explain the types of ion with examples. -Chemistry 9th

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What is Law of conservation of mass and Law of constant proportions? -Chemistry 9th

Description : What is Law of conservation of mass and Law of constant proportions? -Chemistry 9th

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What is formula unit of mass? How is it different from molecular mass? -Chemistry 9th

Description : What is formula unit of mass? How is it different from molecular mass? -Chemistry 9th

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Description : Define polyatomic ion. Give one example. -Chemistry 9th

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Find the mass of 0.5 moles of CaCO3 -Chemistry 9th

Description : Find the mass of 0.5 moles of CaCO3 -Chemistry 9th

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Mendeleev arranged the elements in his periodic table on the basis of

Description : Mendeleev arranged the elements in his periodic table on the basis of

Last Answer : atomic mass.

How many elements did Mendeleev introduce the modern periodic table ?

Description : How many elements did Mendeleev introduce the modern periodic table ?

Last Answer : Mendeleev introduced the modern periodic table with 67 elements.

What did Moseley use to reorder the elements of Mendeleev periodic table?

Description : What did Moseley use to reorder the elements of Mendeleev periodic table?

Last Answer : Henry Moseley discovered a relation between X-ray spectra and the atomic number of chemical elements.