explain mendelev periodic table
Answers
Answer:
Definition Of Mendeleev? s Periodic Table. In 18690 Russian chemist Dmitri Mendeleev Published a Periodic Table and corresponding periodic law of 63 elements known at that time. Mendeleev's Periodic Law states that “The Physical and Chemical Properties of the elements are periodic functions of their atomic weights.”
Explanation:
Mendeleev’s Periodic Table:
Mendeleev arranged the elements known at that time in order of increasing atomic masses and this arrangement was called periodic table . Elements with similar characteristics were present in vertical rows called groups. The horizontal rows were known as periods.
Characteristics of the Periodic Table:
The main characteristics of the periodic table are:
(1) In the periodic table, the elements are arranged in vertical rows called groups and horizontal rows known as periods.
(2) There are eight groups indicated by Roman Numerals as I, II, III, IV, V, VI, VII, VIII and the elements belonging to the first seven groups have been divided into sub-groups designated as A and B on the basis of similarities in properties.
(3) The elements that are present on the left hand side in each group constitute sub-group A while those on the right hand side form sub-group B. Group VIII consists of nine elements which are arranged in three triads.
(4) There are six periods (numbered from 1 to 6) or horizontal rows in the Mendeleev’s periodic table. The periods 4, 5 and 6 are divided into two halves. The first half of the elements are placed in the upper left corners and the second half occupy lower right corners in each box.
5) Many gaps were left in the periodic table for the undiscovered elements which were identified later on and were placed at their respective positions.
6) Noble gases could be easily placed in a separate group called zero group (noble gas elements have zero valency) without disturbing the main periodic table.
Hope it helps!