The elements were arranged in increasing order of their atomic mass,the properties of every eighth element were similar to those of the first one,this was found by

Ionic radii are

The fourteen elements from Th to Lr are known as

Which block consists of elements of groupI(IA)and (IIA) ?

Which one of the following orders is not in accordance with the property stated against it ?

Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species?

With which of the following electronic configuration an atom has the lowest ionisation enthalpy ?

Pauling's electro negativity values for elements are useful in predicting

Elements could be arranged in a group of three called triad in such a way that the middle element had an atomic weight almost the average of the other two,this was found by 

The ionisation of hydrogen atom would give rise to