The element with atomic number $14$ is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

Which of the following are the characteristics of isotopes of an element?
$(i)$ Isotopes of an element have same atomic masses
$(ii)$ Isotopes of an element have same atomic number
$(iii)$ Isotopes of an element show same physical properties
$(iv)$ Isotopes of an element show same chemical properties

Three elements $X$,$Y$,and $Z$ having atomic numbers $11$,$7$,and $6$ respectively react with oxygen to form their oxides.
$(a)$ Arrange these oxides in increasing order of their basic nature.
$(b)$ Give reason for your answer.

What is the position of metalloids in the periodic table?

Write true or false for the statement: Electronic configuration of hydrogen resembles that of alkaline earth metals.

Which of the following is the outermost shell for elements of period $2$?