Question 1 :
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 2 :
The sum of the number of elements of fifth and sixth period is :

Question 5 :
Atomic wt. of P is 31 and Sb is 120. What will be the atomic wt. of As, as per Dobernier triad rule?

Question 9 :
___________ said that cathode rays consist of negatively charged particles and these were named as electrons.

Question 13 :
A neutral atom of an element has a nucleus with nuclear charge $11$ times and mass $23$ times that of hydrogen. Find the ratio of no. of electrons to protons present in its stable ion.

Question 14 :
The $\displaystyle \frac {e}{m}$ ratio of an electron for all types of substances is :

Question 15 :
Match the values of column II with column I and mark the appropriate choice.<br><table class="wysiwyg-table"><tbody><tr><td></td><td>Column I</td><td></td><td>Column II</td></tr><tr><td>(A)</td><td>Mass of electron</td><td>(i)</td><td>$1.673\times 10^{-27}$ kg</td></tr><tr><td>(B)</td><td>Mass of proton</td><td>(ii)</td><td>$-1.602\times 10^{-19}$ C</td></tr><tr><td>(C)</td><td>Charge of electron</td><td>(iii)</td><td>$9.1\times 10^{-31}$Kg</td></tr><tr><td>(D)</td><td>e/m for an electron</td><td>(iv)</td><td>$1.76\times 10^8 $C/g</td></tr></tbody></table>

Question 16 :
The mass and charge of one mole of electrons, respectively is:

Question 19 :
Which of the following statement is incorrect for formation of sodium chloride?

Question 21 :
How many dots should be around each elemental symbol in a Lewis dot diagram?

Question 22 :
You have three solids. One is a metal; one is an ionic compound; one is a molecular/covalent compound. You test all three solid samples to identify their bonding.<br/><table class="wysiwyg-table"><tbody><tr><td>Sample</td><td>Appearance</td><td>Melting Point $(<br/>^{\circ}C)$</td><td>Conductivity</td></tr><tr><td>A</td><td>Shiny</td><td>$962$</td><td>conductive</td></tr><tr><td>B</td><td>Crystalline</td><td>$801$</td><td>conductive in aqueous solution</td></tr><tr><td>C</td><td>Powdery</td><td>$186$</td><td>not conductive<br/></td></tr></tbody></table><br/>Based on this data, identify the type of bonds present in each sample.