Which of the following statement about the modern periodic table is correct?

The atomic numbers of four elements P, Q, R and S are 6, 8, 14 and 16 respectively. Out of these, the element known as metalloid is

Which of the following statement is correct in regard to the classification of elements ?

An element X forms an oxide X₂O₃. In which group of Mendeleev’s periodic table is this element placed ?

The modern periodic table was prepared by :