Posts tagged: Important Questions

Classification of Elements and Periodicity in Propenties
Q1. How many groups and periods were there in the original Mendeleev's Periodic Table?
Q2. State the Modern Periodic Law.
Q3. What is the main features of long form of periodic table?
Q4. How many groups and periods are there in the long form of the periodic table?
Q5. Write the electronic configuration of scandium having atomic number 21.
Q6. Out of nitrogen and oxygen, which has higher value of first ionization enthalpy?
Q7. Explain the term electron gain enthalpy.
Q8. Why is the electron gain enthalpy of nitrogen is zero?
Q9. How do electronegativity of elements behave in a period?
Q10.In $\mathrm{K}$$\mathrm{K}$K\mathrm{K}$\mathrm{K}$ and ${\mathrm{K}}^{+}$${\mathrm{K}}^{+}$K^(+)\mathrm{K}^{+}${\mathrm{K}}^{+}$, which one would have larger size?
Q11.In $\mathrm{B}\mathrm{r}$$\mathrm{B}\mathrm{r}$Br\mathrm{Br}$\mathrm{B}\mathrm{r}$ and ${\mathrm{B}\mathrm{r}}^{-}$${\mathrm{B}\mathrm{r}}^{-}$Br^(-)\mathrm{Br}^{-}${\mathrm{B}\mathrm{r}}^{-}$, which one would have larger size?
Q12.In ${\mathrm{O}}^{2-}$${\mathrm{O}}^{2-}$O^(2-)\mathrm{O}^{2-}${\mathrm{O}}^{2-}$ and ${\mathrm{F}}^{-}$${\mathrm{F}}^{-}$F^(-)\mathrm{F}^{-}${\mathrm{F}}^{-}$, which one would have larger size?
Q13.In ${\mathrm{L}\mathrm{i}}^{+}$${\mathrm{L}\mathrm{i}}^{+}$Li^(+)\mathrm{Li}^{+}${\mathrm{L}\mathrm{i}}^{+}$and ${\mathrm{N}\mathrm{a}}^{+}$${\mathrm{N}\mathrm{a}}^{+}$Na^(+)\mathrm{Na}^{+}${\mathrm{N}\mathrm{a}}^{+}$, which one would have larger size?
Q14.What is meant by isoelectronic species?
Q15.Arrange the following elements in the increasing order of metallic character.
Q16.Arrange the following elements in the increasing order of non-metallic character:
Q17.Predict the position of the elements in the periodic table satisfying the electron configuration
( $\mathrm{n}-$$\mathrm{n}-$n-\mathrm{n}-$\mathrm{n}-$ 1) $d^{1}n{s}^2$$d^{1}n{s}^2$d^(1)ns^(2)d^1 n s^2$d^{1}n{s}^2$ for $n=4$$n=4$n=4n=4$n=4$.
Q18.Elements A, B, C, D and $\mathrm{E}$$\mathrm{E}$E\mathrm{E}$\mathrm{E}$ have the following electronic configurations:
A: $1s^{2}2s^{2}2p^1$$1s^{2}2s^{2}2p^1$1s^(2)2s^(2)2p^(1)1 s^2 2 s^2 2 p^1$1s^{2}2s^{2}2p^1$
B: $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$$1s^{2}2s^{2}2p^{6}3s^{2}3p^1$1s^(2)2s^(2)2p^(6)3s^(2)3p^(1)1 s^2 2 s^2 2 p^6 3 s^2 3 p^1$1s^{2}2s^{2}2p^{6}3s^{2}3p^1$
C: $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$$1s^{2}2s^{2}2p^{6}3s^{2}3p^3$1s^(2)2s^(2)2p^(6)3s^(2)3p^(3)1 s^2 2 s^2 2 p^6 3 s^2 3 p^3$1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
D: $1s^{2}2s^{2}2p^{6}3s^{2}3p^5$$1s^{2}2s^{2}2p^{6}3s^{2}3p^5$1s^(2)2s^(2)2p^(6)3s^(2)3p^(5)1 s^2 2 s^2 2 p^6 3 s^2 3 p^5$1s^{2}2s^{2}2p^{6}3s^{2}3p^5$
E: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$
Which among these will belong to the same group in the periodic table?
Q19.What would be the IUPAC name and symbol for the element with atomic number 120 ?
Q20.Write the atomic number of the element present in the third period and seventeenth group of the periodic table.
Q21.The first ionization enthalpy $\left({\mathrm{\Delta }}_{\mathrm{i}}\mathrm{H}\right)$$\left({\mathrm{\Delta }}_{\mathrm{i}}\mathrm{H}\right)$(Delta_(i)H)\left(\Delta_{\mathrm{i}} \mathrm{H}\right)$\left({\mathrm{\Delta }}_{\mathrm{i}}\mathrm{H}\right)$ values of the third period elements, $\mathrm{N}\mathrm{a},\mathrm{M}\mathrm{g}$$\mathrm{N}\mathrm{a},\mathrm{M}\mathrm{g}$Na,Mg\mathrm{Na}, \mathrm{Mg}$\mathrm{N}\mathrm{a},\mathrm{M}\mathrm{g}$, and $\mathrm{S}\mathrm{i}$$\mathrm{S}\mathrm{i}$Si\mathrm{Si}$\mathrm{S}\mathrm{i}$ are respectively 496,737 and $786\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$$786\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$786kJmol^(-1)786 \mathrm{~kJ} \mathrm{~mol}^{-1}$786\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$. Predict whether the first ${\mathrm{\Delta }}_{\mathrm{j}}\mathrm{H}$${\mathrm{\Delta }}_{\mathrm{j}}\mathrm{H}$Delta_(j)H\Delta_{\mathrm{j}} \mathrm{H}${\mathrm{\Delta }}_{\mathrm{j}}\mathrm{H}$ value for Al will be more close to 575 or $760\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$$760\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$760kJmol^(-1)760 \mathrm{~kJ} \mathrm{~mol}^{-1}$760\mathrm{k}\mathrm{J}{\mathrm{m}\mathrm{o}\mathrm{l}}^{-1}$ Justify your answer.
Q22.Explain why first ionization enthalpy of nitrogen is
higher than that of elements on left and right hand side in the same period (i.e., carbon and oxygen).
Q23.Among the elements $\mathrm{L}\mathrm{i},\mathrm{K},\mathrm{C}\mathrm{a},\mathrm{S}$$\mathrm{L}\mathrm{i},\mathrm{K},\mathrm{C}\mathrm{a},\mathrm{S}$Li,K,Ca,S\mathrm{Li}, \mathrm{K}, \mathrm{Ca}, \mathrm{S}$\mathrm{L}\mathrm{i},\mathrm{K},\mathrm{C}\mathrm{a},\mathrm{S}$ and $\mathrm{K}\mathrm{r}$$\mathrm{K}\mathrm{r}$Kr\mathrm{Kr}$\mathrm{K}\mathrm{r}$, which one has the lowest first ionization enthalpy and which one has the highest first ionization enthalpy?
Q24. Which of the following pairs of elements would you expect to have lower first ionization enthalpy?
(i) $\mathrm{C}\mathrm{l}$$\mathrm{C}\mathrm{l}$Cl\mathrm{Cl}$\mathrm{C}\mathrm{l}$ or $\mathrm{F}$$\mathrm{F}$F\mathrm{F}$\mathrm{F}$, (ii) $\mathrm{C}\mathrm{l}$$\mathrm{C}\mathrm{l}$Cl\mathrm{Cl}$\mathrm{C}\mathrm{l}$ or $\mathrm{S}$$\mathrm{S}$S\mathrm{S}$\mathrm{S}$, (iii) $\mathrm{K}$$\mathrm{K}$K\mathrm{K}$\mathrm{K}$ or $\mathrm{A}\mathrm{r}$$\mathrm{A}\mathrm{r}$Ar\mathrm{Ar}$\mathrm{A}\mathrm{r}$ and (iv) $\mathrm{K}\mathrm{r}$$\mathrm{K}\mathrm{r}$Kr\mathrm{Kr}$\mathrm{K}\mathrm{r}$ or $\mathrm{X}\mathrm{e}$$\mathrm{X}\mathrm{e}$Xe\mathrm{Xe}$\mathrm{X}\mathrm{e}$.
Q25.Second and third ionization enthalpies of an element are always greater than its first ionization enthalpy. Explain.
Q26.Electron gain enthalpy values of inert gases are zero. Why?
Q27.Electron gain enthalpy of halogens are high? Explain.
Q28.Define the term electronegativity. Explain.
Q29.Electronegativity values of inert gases are zero. Explain.
Q30.Give the formula of a species that will be isoelectronic with the following atoms or ions: (i) $\mathrm{N}\mathrm{e}$$\mathrm{N}\mathrm{e}$Ne\mathrm{Ne}$\mathrm{N}\mathrm{e}$ (ii) ${\mathrm{C}\mathrm{l}}^{-}$${\mathrm{C}\mathrm{l}}^{-}$Cl^(-)\mathrm{Cl}^{-}${\mathrm{C}\mathrm{l}}^{-}$(iii) ${\mathrm{C}\mathrm{a}}^{2+}$${\mathrm{C}\mathrm{a}}^{2+}$Ca^(2+)\mathrm{Ca}^{2+}${\mathrm{C}\mathrm{a}}^{2+}$ (iv) ${\mathrm{R}\mathrm{b}}^{+}$${\mathrm{R}\mathrm{b}}^{+}$Rb^(+)\mathrm{Rb}^{+}${\mathrm{R}\mathrm{b}}^{+}$.