Which of the following is the most electropositive element?

What is the correct order of basicity of halides?

Given below are two statements:
Statement $I$ : Both metal and non-metal exist in $p$ and $d-$block elements.
Statement $II$ : Non-metals have higher ionisation enthalpy and higher electronegativity than the metals.
In the light of the above statements,choose the most appropriate answer from the option given below:

Which of the following oxides is the most basic oxide?

The correct set that contains all kinds (basic,acidic,amphoteric,and neutral) of oxides is:

In known elements,the maximum number is of