يوليو 16th, 2018

 

Mendeleev’s periodic law

Mendeleev’s periodic law

Mendeleev gave a periodic law in 1869. According to Mendeleev’s periodic law, the properties, of elements are periodic functions of their atomic masses. He found that if the elements are arranged in the order of increasing atomic masses, then the properties of elements are repeated after regular intervals or periods.

Important features of Mendeleev’s periodic table:

1 – The table…

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Newland’s Law of Octaves

Newland’s Law of Octaves

In 1866 Newland found that when elements are arranged according to increasing atomic masses, the properties of the eight element (starting from a given one) are repetition of the properties of the first element. If we start from lithium (Li) we find that the eighth element from it is sodium (Na). So according to Newland the properties of eighth element, sodium should be…

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Dobereinier’s law of tirade

Dobereinier’s law of tirade

In 1817 Dobereiner found that when elements are arranged in the order of increasing atomic masses, groups of three elements (known as triads) having similar chemical properties are obtained. The atomic mass of the middle element was found to be the average of the rest of the two :

 

Li                  Na                  K

7                   23                  39

Na = (7 +…

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Hund’s rule of maximum multiplicity

It states that no electron pairing takes place in the p, d and f orbitals until all the orbitals of the given sub-shell contain 1 electron each with parallel spins.

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