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26 Nov

Periodic Law Class 10

Previous attempts at classifying elements: Dobereiner`s triads, Newland`s octave law. (iii) Metallic and non-metallic properties: In the modern periodic table, metals are on the left and nonmetals are on the right side of the table. A zigzag line of metalloids separates metals from nonmetals. Question 2 How many groups and periods are there in the modern periodic table? Thanks, Mom. With this, we do not want to refer to the periodic law of the Mendleev manual 6) noble gases could easily be classified into a separate group called group zero (noble gas elements have a zero value) without disturbing the main periodic table. (4) The positions of some elements that were erroneous in Mendeleev`s periodic table are now justified because they are based on the atomic number of the elements. Question 7 How was the position of an element`s isotopes in the modern periodic table determined? Mendeleev placed more emphasis on the similarity of properties than on increasing the atomic masses of the elements. Thus, if a certain element did not fit the arrangement, it left a gap in the periodic table. Thus, many gaps were left for elements not discovered in Mendeleev`s periodic table.

Question 2 What did Mendeleev use to classify the elements? Limits of Mendeleev`s periodic table (a) No fixed position for hydrogen: No correct position of the hydrogen atom was in Mendeleev`s periodic table. Example: Position of hydrogen with alkali metals and halogens (17th group). Periodic trends are common patterns in the periodic table that show us different aspects of an element such as electronegativity, atomic radius or ionizing strength. The periodic law tells us that when grouped by atomic number, certain properties of the elements appear periodically. Mendeleev`s periodic table: Mendeleev`s periodic table is based on the physical and chemical properties of elements and their atomic masses. In a given period of time, the electronic configuration of the valence shell of any two elements is not the same. For this reason, elements have different chemical properties over time, with periodic left-to-right gradation for their physical properties. This is called a periodic property. Mendeleev`s original periodic table is presented in the following table Question 5 Why did Mendeleev leave gaps in his periodic table of elements? Modern Periodic Law: This law was proposed in 1913 by Henry Moseley, a scientist.

According to this law, “the properties of elements are the periodic function of their atomic number”. This means that the properties of the elements depend on their atomic number and the elements are assigned positions in the periodic table due to their increasing atomic number. Indeed, the atomic number determines the distribution of electrons in orbits and electrons in the outermost orbit determines the properties of an element. If you still have doubts about the periodic law and want to know more about class 10 of the periodic table, read our introduction to the periodic table for more details. Modern law: The physical and chemical properties of elements are the periodic function of their atomic number. The modern periodic table is based on the atomic number of the elements. The atomic number (Z) is equal to the number of protons present in the nucleus of an atom of an element. The modern periodic table contains 18 vertical columns called groups and seven horizontal lines called points.

Moving from left to right in a period increases the number of valence electrons in existing elements from 1 to 8. When you move from left to right in a period of time, the number of shells remains the same. All elements in a group of the periodic table have the same number of valence electrons. In 1869, Dmitri Mendeleev and Lothar Meyer independently established the law of periods. The first periodic table was developed by Mendeleev and soon followed by Meyer. Each grouped the elements according to their mass and suggested that these properties be reproduced regularly. 1. Need to classify elements: The increasing discovery of different elements made it difficult to organize everything that was known about the elements.

In order to easily study a large number of elements, various attempts have been made. The experiments led to the classification of the elements into metals and non-metals. The development of various atomic models and advances in quantum theory have shown that atomic number is the most fundamental property of a chemical element. This led to the modification of Mendeleev`s law of periods, which is now called modern periodic law. Question 7 What are the characteristics of Mendeleev`s periodic table? The atomic number is equal to the number of electrons or protons in a neutral atom. Having known the fundamental unity of the elements, scientists now had a clear idea of the quantum numbers and the electronic configuration of the elements in the periodic table. After knowing the periodic law, chemists noticed that there is an analogy between the 94 natural chemical elements. This analogy has made people more curious about the chemistry of these elements. Scientists have produced various artificial elements. A new periodic table was developed on the basis of the modern law of periods by modifying Mendeleev`s periodic table. 5. Modern periodic table: Henry Moseley, gave a new one! Property of the elements, “atomic number” and this has been adopted as the basis of the modern periodic table.

(i) Modern periodic law: The properties of elements are a periodic function of i of their atomic number. (ii) The position of elements in the modern periodic table: This is only a brief description of the periodic table and the classification of elements. To learn more, register for BYJU`S and download BYJU`S – the learning app. According to him, atomic numbers should form the basis for the classification of elements in the periodic table. 2. Dobereiner`s triads: Johann Wolfgang Dobereiner, a German chemist, classified known elements into groups of three elements based on similarities in their properties. These groups were called triads. (i) Triad properties: Isotopes of an element have different atomic weights but the same atomic number. Since the periodic table was designed on the basis of increasing the atomic weights of the elements, all isotopes of a particular element must have been assigned to different positions.

Therefore, since the number of electrons in an atom is given by the atomic number and not by the mass number, the atomic number should be the basis for classifying the elements in the periodic table and not the atomic mass, as predicted by Mendeleev. “The physical and chemical properties of elements are periodic functions of their atomic numbers.” (4) There are six periods (numbered 1 to 6) or horizontal lines in Mendeleev`s periodic table. Periods 4, 5 and 6 are divided into two halves. The first half of the items are in the upper left corners and the second half occupies the lower right corners of each box.