Question Text
Question 3 :
The elements having more masses were placed before elements having lower masses in Mendleev's periodic table. Guess the pair of elements (higher mass, lower mass).
Question 6 :
The number of elements known in Mendeleev's presented periodic table is:<br/>
Question 7 :
Arrange the following elements in the order of their decreasing metallic character.Na, Si, Cl, Mg, Al
Question 8 :
Which element has a dicey position in the modern periodic table?
Question 10 :
The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. Such an arrangement of elements called as :<br/>
Question 11 :
Compare the radii of two species X and Y.<br/>(a) X has 12 protons and 12 electrons.<br/>(b) Y has 12 protons and 10 electrons.<br/>
Question 13 :
Which of the given elements A, B, C, D and E with atomic number $2,\,3,\,7,\,10$ and $30$ respectively belong to the same period?
Question 14 :
The elements with atomic numbers $9, 17, 35, 53, 85$ are all :