Classification ...

To which of the following atom, the attachment of electron is most difficult?

Element A and B with their respective electronic configurations $$3d^{10}4s^{1}$$ and $$4d^{10}5s^{1}$$ in their outermost shell are 

Mark the group which has maximum number of element in Mendeleev's periodic table:

Refer to change in the properties of elements on moving from left to right across a period of the Periodic Table. For each property, choose the correct answer.
The electronegativity :

The first electron affinity of C, N and O will be of the order: 

Metal T reacts with water to produce a colourless solution. A white precipitate is produced when this colourless solution is mixed with aqueous sulfuric acid. What is metal T?

When burned, sulfur forms a gaseous product X which can be oxidised to produce a gas Y. Gas Y reacts with water to produce a product Z.
Which row correctly shows the oxidation states of sulfur in X, Y and Z?

Which pair of elements will react together most violently?

Which in each has higher electron affinity?

Electronic configuration of chalcogens in their outermost orbit is