![]() Anomalies of Mendeleev’s classification of elements It could also predict the properties of several elements based on their position in the periodic table. When noble gases were discovered, Mendeleev’s periodic table could accommodate them. Mendeleev also placed a few elements in the wrong order of their atomic masses, keeping the element with the higher atomic mass first and the element with the lower atomic mass later, to ensure that elements with similar properties fell into the same vertical column. When these elements were discovered later on, then eka-boron was named scandium, eka-aluminium was named gallium, and eka-silicon was named germanium. The undiscovered or the unknown elements at the time for which the gaps were left in the periodic table were named by Mendeleev as eka-boron, eka-aluminium, and eka-silicon. To make sure that the elements having similar properties fell in the same vertical column, Mendeleev left some gaps in his table. ![]() So, in Mendeleev’s original periodic table, there was no group of noble gases. In Mendeleev’s periodic table, there were seven horizontal rows called periods and eight vertical columns called groups. Mendeleev arranged all 63 elements known at the time in the periodic table in horizontal rows in order of increasing atomic masses, but in such a way that elements with similar properties were placed together in the same vertical column. In 1869, Mendeleev proposed the periodic law, which states that if elements are arranged in increasing atomic mass order, their properties will be repeated at regular intervals or periods. Mendeleev’s periodic table and its anomalies or limitations are discussed below. But there were always some limitations to these classifications until the Modern periodic table. Dobereiner’s Triads, Newland’s law of octaves, Mendeleev’s periodic table all helped to classify the known elements. The study of a large number of elements is reduced to a few groups of elements if all the elements are divided into a few groups, in such a way that elements in the same group have similar properties. Arithmetic Progression - Common difference and Nth term | Class 10 Maths.Area of a Triangle - Coordinate Geometry | Class 10 Maths.Class 10 RD Sharma Solutions- Chapter 2 Polynomials - Exercise 2.1 | Set 2.Electric Potential and Potential Difference.Euclid's Division Algorithm - Real Numbers | Class 10 Maths.Step deviation Method for Finding the Mean with Examples.Theorem - The tangent at any point of a circle is perpendicular to the radius through the point of contact - Circles | Class 10 Maths. ![]()
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