Name the Russian chemist who said that the properties of elements are a periodic function of their atomic masses.

Academic Chemistry NCERT Class 10

Dmitri Mendeleev, the Russian chemist who said that the properties of elements are a periodic function of their atomic masses.

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Updated on: 10-Oct-2022

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According to Mendeleev’s Periodic Law, the elements were arranged in the periodic table in the order of(a) increasing atomic number(b) decreasing atomic number(c) increasing atomic masses(d) decreasing atomic masses
State whether the following statement are true or false:(a) Newlands divided the elements into horizontal rows of eight element each. (b) According to Mendeleev’s periodic law, the properties of elements are a periodic function of their atomic numbers. (c) The elements in a group have consecutive atomic numbers.
Which of the following statement is correct in regard to the classification of elements ?(a) Elements in the periodic table are arranged on the basis of increasing atomic masses (b) Elements in Mendeleev’s periodic table are arranged on the basis of increasing atomic numbers (c) In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass (d) In modern periodic table, the isotopes of chlorine having diffrenet atomic masses are kept in the same group.
Name two elements whose properties were predicted on the basis of their positions in Mendeleev’s periodic table.
Who is a chemist?
Name the scientist who gave atomic theory of matter.
Which of the following statement (s) about the Modern Periodic Table are incorrectThe elements in the Modern Periodic Table are arranged based on their decreasing atomic numberThe elements in the Modern Periodic Table are arranged based on their increasing atomic massesIsotopes are placed in adjoining group (s) in the Periodic TableThe elements in the Modern Periodic Table are arranged based on their increasing atomic number(a) (i) only(b) (i), (ii) and (iii)(c) (i), (ii) and (iv) (d) (iv) only
In Mendeleev’s Periodic Table the elements were arranged in the increasing order of their atomic masses. However, cobalt with an atomic mass of 58.93 amu was placed before nickel having an atomic mass of 58.71 amu. Give a reason for the same.
Explain why, the atomic masses of many elements are in fractions and not whole numbers.
The following diagram shows a part of the periodic table in which the elements are arranged according to their atomic numbers. (The letters given here not the chemical symbols of the elements):
Name of 118 elements in the periodic table.
Around the year 1800, only 30 elements were known. Dobereiner in 1817 and Newlands in 1866 tried to arrange the then-known elements and framed laws which were rejected by the scientists. Even after the rejection of the proposed laws, many scientists continued to search for a pattern that correlated the properties of elements with their atomic masses.The main credit for classifying elements goes to Mendeleev for his most important contribution to the early development of a Periodic table of elements wherein he arranged the elements on the basis of their fundamental property, the atomic mass, and also on the similarity of chemical properties. The formulae of their hydrides and oxides were treated as basic criteria for the classification of the elements.However, Mendeleev’s classification also had some limitations as it could not assign the position to isotopes. He also left some gaps in the periodic table.(a) State Mendeleev’s Periodic Law.(b) Why did Mendeleev leave some gaps in the Periodic table?(c) If the letter ‘R’ was used to represent any of the elements in the group, then the hydride and oxide of carbon would respectively be represented as(i) RH4, RO (ii) RH4, RO2(iii) RH2, RO2 (iv) RH2, RO(d) Isotopes are-(i) Atoms of an element with similar chemical properties but different atomic masses. (ii) Atoms of different elements with similar chemical properties but different atomic masses. (iii) Atoms of an element with different chemical properties but same atomic masses. (iv) Atoms of different elements with different chemical properties but same atomic masses.
(a) In this ladder (Figure 5.2) symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.(b) Arrange them in the order of their group also."
Elements have been arranged in the following sequence on the basis of their increasing atomic masses. F, Na, Mg, Al, Si, P, S, Cl, Ar, K (a) Pick two sets of elements which have similar properties.(b) The given sequence represents which law of classification of elements?
(a) Explain why:(i) All the elements of a group have similar chemical properties. (ii) All the elements of a period have different chemical properties. (b) The atomic radii of three elements X, Y, and Z of a period of the periodic table are 186 pm; 104 pm, and 143 pm respectively. Giving a reason, arrange these elements in the increasing order of atomic numbers in the period.

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