An element which never has a positive oxidation number in any of its compounds is:

Electronic configuration of four elements $A, B, C$ and $D$ are given below $:$
$(A) 1s^2 2s^2 2p^3$
$(B) 1s^2 2s^2 2p^4$
$(C) 1s^2 2s^2 2p^5$
$(D) 1s^2 2s^2 2p^2$
Which of the following is the correct order of increasing electronegativity $(Pauling's scale)$?

In which of the following pairs of elements is the electronegativity of the first element less than that of the second element?

For $AB$ bond,if percent ionic character is plotted against electronegativity difference $(X_A - X_B)$,the shape of the curve would look like. The correct curve is:

Which of the following elements never shows a positive oxidation number?

Arrange the following bonds in order of increasing ionic character: $C-O, C-N$ and $C-C$. Give reasons.