Classification ...

Mendeleev classified elements in:

The total number of elements in the group $IB$ is:

Identify the electronic configuration of an element whose atomic radii is determined by taking half the internuclear distance between like atoms.

Barium (Ba) belongs to group:

To which block is an element, having electronic configuration $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^1$, related in the periodic table?

Arrange $S,\ O$ and $Se$ in ascending order of their electron affinity.

An element with $Z = 46$ belongs to :

Ratio of radii of K, L, M shells of hydrogen atom is :

Atomic radii of $3$ non-metals $A, B, C$ belonging to the same group are in the order $A < B < C$. Predict the order of electron affinity values.

Number of elements in 6th period are: