Assertion (A): | The shielding effect increase as we go down the group. |
Reason (R): | More is the number of electrons in the penultimate shell, and more is shielding. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Statement I: | Generally, only non-metal oxides are acidic but oxides of some metals in high oxidation state are also found to have an acidic character. |
Statement II: |
Oxides like CO, NO, and N2O are neutral oxides. |
1. | X is an alkali metal and Y is an alkaline earth metal. |
2. | X is an alkaline earth metal and Y is an alkali metal. |
3. | Both X and Y are alkali metals. |
4. | Both X and Y are alkaline earth metals. |
1. | Lothar Meyer plotted the physical properties against the atomic number and obtained a periodically repeated pattern. |
2. | French geologist, Chancourtois made a cylindrical table of elements to display the periodic recurrence of properties. |
3. | Mendeleev realized that some of the elements did not fit in with his scheme of classification if the order of atomic number was strictly followed. |
4. | Seaborg was awarded the Nobel Prize in chemistry for his work and Element 101 has been named Seaborgium (Sg) in his honour. |
Assertion (A): | First ionization energy for nitrogen is lower than that of oxygen. |
Reason (R): | Across a period, effective nuclear charge decreases. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
1. | O and Cl | 2. | N and Cl |
3. | N and Br | 4. | C and Br |
The most basic oxide among the following is:
1. Bi2O3
2. Bi2O5
3. As2O3
4. Sb2O5