Mendeleev’s periodic table had …………… elements. 

Features of Mendeleev’s periodic table: In Mendeleev’s periodic table, all 63 elements were arranged in an increasing order of their atomic masses. The serial or ordinal number of an element in...

Mendeleev’s periodic table was readily accepted by scientific community due to the following advantages: i. Mendeleev had left some gaps corresponding to certain atomic numbers in the periodic table so as...

Henry Moseley in 1913, studied X-ray spectra of large number of elements. He observed that the frequency of X-ray emitted from an element is related to atomic number (Z) of an...

i. First period  ii. f-Block

Correct option is (C) 63 At that time, Mendeleev's periodic table had 63 elements.

Correct option is : (D) proton number The serial number of an element in Mendeleev's periodic table was recognized as proton number.

Correct option is: (A) atomic weights According to Mendeleev's periodic law, the Physical and Chemical properties of elements are the periodic function of their atomic weight

The Modern periodic table removed various anomalies of Mendeleev’s periodic table as follows:  i. All isotopes of the same element have different atomic masses but same atomic number. Therefore, they occupy...