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

The serial or ordinal number of an element in Mendeleev’s periodic table was recognized as ………….

Mendeleev predicted the existence of …………

According to Mendeleev’s periodic law, the physical and chemical properties of elements are the periodic function of their ………

Moseley showed that the fundamental property of an element is …………

According to periodic law of elements, the variation in properties of elements is related to their ………

At present, how many elements are known?

The long form of the periodic table consists of how many periods?

According to quantum mechanical model of the atom, the properties of elements can be correlated to their …………

The fourth, fifth and sixth periods are long periods and contain ……………