Question

class -10 periodic classification of element notes​

Answer 1

Answer:

The notes on Periodic Classification of Elements are:

• Dobereiner's Triad- In 1817, Johann Dobereiner presented three triads of three related elements, each in ascending order of atomic mass. He claimed that the arithmetic mean of the middle element is about equal to the sum of the atomic masses of the first and third elements.
• Newland's Law of Octave- John Newlands ordered the 56 known elements at the time in 1866 in ascending order of atomic mass. According to him, the initial element's characteristics are shared by every eighth element. Drawbacks: Only applies to lighter elements up until calcium, which has an atomic number of 40. In his table, recently found components did not fit. Ni and Co are two elements that are located next to other elements with distinct qualities, like chlorine, but apart from other elements with comparable properties, like iron.
• Mendeleev's Periodic Table- It has two main factors to take into account: order of increasing atomic masses. Formulas for elemental hydrides and oxides. (Elements that produce compounds with similar formulas and have comparable properties were grouped together.) Gave rise to the periodic law, according to which an element's properties are a periodic function of its atomic mass. It had 7 periods and 8 groups.
• Modern Periodic Table- Focuses on Henry Moseley's 1913 suggestion that atomic numbers be prioritized over atomic masses. Modified the periodic law: an element's atomic number determines its attributes in a periodic manner. It has 7 periods and 18 groups. The quantity of valence electrons shared by all the elements in a group determines the electrical arrangement of the outer shell. The number of occupied shells is the same for all elements within the same period.
• Valency- As we move over a period from left to right, there are first increases and then reductions. The valency of elements in the same group is the same.
• Atomic Radius- Atomic size shrinks as we travel through a period. The same shell receives an additional electron, which has a tendency to be strongly drawn toward the nucleus. Atomic size and radius decrease as nuclear charge increases. Atomic size grows as we travel along a group. A new shell is added following each component in a group. While electrons are also added, their impact is not as great as that of additional shells due to the higher nuclear charge. As a result, atomic size grows.
• Metal Characteristics- The amount of metallic character rises as we descend a group. Down a group, valence electrons are further from the nucleus. The net nuclear charge is decreasing, making it simpler to shed electrons and produce positive ions. (electropositivity) Metallic character diminishes as we travel through a time.

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