Q3.28:

The increasing order of reactivity among group 1 elements is (Li < Na < K < Rb < Cs) whereas that among group 17 elements is (F > CI > Br > I). Explain.

More Questions from Class 11 Chemistry Classification of Elements and Periodicity in Properties EXERCISES

• Q3.1: What is the basic theme of organisation in the periodic table?
• Q3.1: What is the basic theme of organisation in the periodic table?
• Q3.10: How do atomic radius vary in a period and in a group? How do you explain the variation?
• Q3.10: How do atomic radius vary in a period and in a group? How do you explain the variation?
• Q3.11(i): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (i) $F^{-}$
• Q3.11(i): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (i) (F^{-})
• Q3.11(ii): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (ii) $Ar$
• Q3.11(ii): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (ii) Ar
• Q3.11(iii): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (iii) $Mg^{2+}$
• Q3.11(iii): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (iii) (Mg^{2+})
• Q3.11(iv): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (iv) $Rb^{+}$
• Q3.11(iv): What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions. (iv) (Rb^{+})
• Q3.12(a): Consider the following species : $N^{3-}$, $O^{2-}$, $F^{-}$, $Na^{+}$, $Mg^{2+}$ and $Al^{3+}$ (a) What is common in them?
• Q3.12(a): Consider the following species: (N^{3-}), (O^{2-}), (F^{-}), (Na^{+}), (Mg^{2+}) and (Al^{3+}) (a) What is common in them?
• Q3.12(b): Consider the following species : $N^{3-}$, $O^{2-}$, $F^{-}$, $Na^{+}$, $Mg^{2+}$ and $Al^{3+}$ (b) Arrange them in the order of increasing ionic radii.
• Q3.12(b): Consider the following species: (N^{3-}), (O^{2-}), (F^{-}), (Na^{+}), (Mg^{2+}) and (Al^{3+}) (b) Arrange them in the order of increasing ionic radii.
• Q3.13: Explain why cation are smaller and anions larger in radii than their parent atoms?
• Q3.13: Explain why cation are smaller and anions larger in radii than their parent atoms?
• Q3.14: What is the significance of the terms — ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy?
• Q3.14: What is the significance of the terms — ‘isolated gaseous atom’ and ‘ground state’ while defining the ionization enthalpy and electron gain enthalpy? Hint : Requirements for comparison purposes.
• Q3.15: Energy of an electron in the ground state of the hydrogen atom is $-2.18 imes 10^{-18}J$. Calculate the ionization enthalpy of atomic hydrogen in terms of $J mol^{-1}$.
• Q3.15: Energy of an electron in the ground state of the hydrogen atom is (–2.18 \times 10^{-18}J). Calculate the ionization enthalpy of atomic hydrogen in terms of (J mol^{-1}). Hint: Apply the idea of mole concept to derive the answer.
• Q3.16(i): Among the second period elements the actual ionization enthalpies are in the order $Li < B < Be < C < O < N < F < Ne$. Explain why (i) $Be$ has higher $\Delta_{i} H$ than $B$
• Q3.16(i): Among the second period elements the actual ionization enthalpies are in the order (Li < B < Be < C < O < N < F < Ne). Explain why (i) Be has higher (\Delta_{i}H) than B
• Q3.16(ii): Among the second period elements the actual ionization enthalpies are in the order $Li < B < Be < C < O < N < F < Ne$. Explain why (ii) $O$ has lower $\Delta_{i} H$ than $N$ and $F$?
• Q3.16(ii): Among the second period elements the actual ionization enthalpies are in the order (Li < B < Be < C < O < N < F < Ne). Explain why (ii) O has lower (\Delta_{i}H) than N and F?
• Q3.17: How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?
• Q3.17: How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?
• Q3.18: What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?
• Q3.18: What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?
• Q3.19: The first ionization enthalpy values (in $kJ mol^{-1}$) of group 13 elements are : B Al Ga In Tl 801 577 579 558 589 How would you explain this deviation from the general trend ?
• Q3.19: The first ionization enthalpy values (in (kJ mol^{-1})) of group 13 elements are : B 801, Al 577, Ga 579, In 558, Tl 589 How would you explain this deviation from the general trend ?
• Q3.2: Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?
• Q3.2: Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?
• Q3.20(i): Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) $O$ or $F$
• Q3.20(i): Which of the following pairs of elements would have a more negative electron gain enthalpy? (i) O or F
• Q3.20(ii): Which of the following pairs of elements would have a more negative electron gain enthalpy? (ii) $F$ or $Cl$
• Q3.20(ii): Which of the following pairs of elements would have a more negative electron gain enthalpy? (ii) F or Cl
• Q3.21: Would you expect the second electron gain enthalpy of $O$ as positive, more negative or less negative than the first? Justify your answer.
• Q3.21: Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.
• Q3.22: What is the basic difference between the terms electron gain enthalpy and electronegativity?
• Q3.22: What is the basic difference between the terms electron gain enthalpy and electronegativity?
• Q3.23: How would you react to the statement that the electronegativity of $N$ on Pauling scale is 3.0 in all the nitrogen compounds?
• Q3.23: How would you react to the statement that the electronegativity of N on Pauling scale is 3.0 in all the nitrogen compounds?
• Q3.24(a): Describe the theory associated with the radius of an atom as it (a) gains an electron
• Q3.24(a): Describe the theory associated with the radius of an atom as it (a) gains an electron
• Q3.24(b): Describe the theory associated with the radius of an atom as it (b) loses an electron
• Q3.24(b): Describe the theory associated with the radius of an atom as it (b) loses an electron
• Q3.25: Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.
• Q3.25: Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.
• Q3.26: What are the major differences between metals and non-metals?
• Q3.26: What are the major differences between metals and non-metals?
• Q3.27(a): Use the periodic table to answer the following questions. (a) Identify an element with five electrons in the outer subshell.
• Q3.27(a): Use the periodic table to answer the following questions. (a) Identify an element with five electrons in the outer subshell.
• Q3.27(b): Use the periodic table to answer the following questions. (b) Identify an element that would tend to lose two electrons.
• Q3.27(b): Use the periodic table to answer the following questions. (b) Identify an element that would tend to lose two electrons.
• Q3.27(c): Use the periodic table to answer the following questions. (c) Identify an element that would tend to gain two electrons.
• Q3.27(c): Use the periodic table to answer the following questions. (c) Identify an element that would tend to gain two electrons.
• Q3.27(d): Use the periodic table to answer the following questions. (d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.
• Q3.27(d): Use the periodic table to answer the following questions. (d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.
• Q3.28: The increasing order of reactivity among group 1 elements is $Li < Na < K < Rb < Cs$ whereas that among group 17 elements is $F > Cl > Br > I$. Explain.
• Q3.29: Write the general outer electronic configuration of $s$-, $p$-, $d$- and $f$- block elements.
• Q3.29: Write the general outer electronic configuration of s-, p-, d- and f- block elements.
• Q3.3: What is the basic difference in approach between the Mendeleev’s Periodic Law and the Modern Periodic Law?
• Q3.3: What is the basic difference in approach between the Mendeleev’s Periodic Law and the Modern Periodic Law?
• Q3.30(i): Assign the position of the element having outer electronic configuration (i) $ns^{2}np^{4}$ for $n=3$
• Q3.30(i): Assign the position of the element having outer electronic configuration (i) (ns^{2}np^{4}) for (n=3)
• Q3.30(ii): Assign the position of the element having outer electronic configuration (ii) $(n-1)d^{2}ns^{2}$ for $n=4$, and
• Q3.30(ii): Assign the position of the element having outer electronic configuration (ii) ((n-1)d^{2}ns^{2}) for (n=4)
• Q3.30(iii): Assign the position of the element having outer electronic configuration (iii) $(n-2) f^{7} (n-1)d^{1}ns^{2}$ for $n=6$, in the periodic table.
• Q3.30(iii): Assign the position of the element having outer electronic configuration (iii) ((n-2)f^{7}(n-1)d^{1}ns^{2}) for (n=6), in the periodic table.
• Q3.31(a): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (a) the least reactive element.
• Q3.31(a): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: Which of the above elements is likely to be : (a) the least reactive element.
• Q3.31(b): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (b) the most reactive metal.
• Q3.31(b): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: (b) the most reactive metal.
• Q3.31(c): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (c) the most reactive non-metal.
• Q3.31(c): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: (c) the most reactive non-metal.
• Q3.31(d): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (d) the least reactive non-metal.
• Q3.31(d): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: (d) the least reactive non-metal.
• Q3.31(e): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (e) the metal which can form a stable binary halide of the formula $MX_{2}$($X$=halogen).
• Q3.31(e): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: (e) the metal which can form a stable binary halide of the formula (MX_{2}) (X=halogen).
• Q3.31(f): The first ($\Delta_{i}H_{1}$) and the second ($\Delta_{i}H_{2}$) ionization enthalpies (in kJ $mol^{-1}$) and the ($\Delta_{eg}H$) electron gain enthalpy (in kJ $mol^{-1}$) of a few elements are given below: Elements $\Delta H_{1}$ $\Delta H_{2}$ $\Delta_{eg}H$ I 520 7300 –60 II 419 3051 –48 III 1681 3374 –328 IV 1008 1846 –295 V 2372 5251 +48 VI 738 1451 –40 Which of the above elements is likely to be : (f) the metal which can form a predominantly stable covalent halide of the formula $MX$ ($X$=halogen)?
• Q3.31(f): The first ((\Delta_{i}H_{1})) and the second ((\Delta_{i}H_{2})) ionization enthalpies (in (kJ mol^{-1})) and the ((\Delta_{eg}H)) electron gain enthalpy (in (kJ mol^{-1})) of a few elements are given below: (f) the metal which can form a predominantly stable covalent halide of the formula (MX) (X=halogen)?
• Q3.32(a): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (a) Lithium and oxygen
• Q3.32(a): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (a) Lithium and oxygen
• Q3.32(b): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (b) Magnesium and nitrogen
• Q3.32(b): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (b) Magnesium and nitrogen
• Q3.32(c): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (c) Aluminium and iodine
• Q3.32(c): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (c) Aluminium and iodine
• Q3.32(d): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (d) Silicon and oxygen
• Q3.32(d): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (d) Silicon and oxygen
• Q3.32(e): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (e) Phosphorus and fluorine
• Q3.32(e): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (e) Phosphorus and fluorine
• Q3.32(f): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (f) Element 71 and fluorine
• Q3.32(f): Predict the formulas of the stable binary compounds that would be formed by the combination of the following pairs of elements. (f) Element 71 and fluorine
• Q3.33: In the modern periodic table, the period indicates the value of :
• Q3.33: In the modern periodic table, the period indicates the value of :
• Q3.34: Which of the following statements related to the modern periodic table is incorrect?
• Q3.34: Which of the following statements related to the modern periodic table is incorrect?
• Q3.35: Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?
• Q3.35: Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?
• Q3.36: The size of isoelectronic species — $F^{-}$, $Ne$ and $Na^{+}$ is affected by
• Q3.36: The size of isoelectronic species — (F^{-}), Ne and (Na^{+}) is affected by
• Q3.37: Which one of the following statements is incorrect in relation to ionization enthalpy?
• Q3.37: Which one of the following statements is incorrect in relation to ionization enthalpy?
• Q3.38: Considering the elements $B$, $Al$, $Mg$, and $K$, the correct order of their metallic character is :
• Q3.38: Considering the elements B, Al, Mg, and K, the correct order of their metallic character is :
• Q3.39: Considering the elements $B$, $C$, $N$, $F$, and $Si$, the correct order of their non-metallic character is :
• Q3.39: Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is :
• Q3.4: On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.
• Q3.4: On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.
• Q3.40: Considering the elements $F$, $Cl$, $O$ and $N$, the correct order of their chemical reactivity in terms of oxidizing property is :
• Q3.40: Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is :
• Q3.5: In terms of period and group where would you locate the element with $Z =114$?
• Q3.5: In terms of period and group where would you locate the element with (Z =114)?
• Q3.6: Write the atomic number of the element present in the third period and seventeenth group of the periodic table.
• Q3.6: Write the atomic number of the element present in the third period and seventeenth group of the periodic table.
• Q3.7(i): Which element do you think would have been named by (i) Lawrence Berkeley Laboratory
• Q3.7(i): Which element do you think would have been named by (i) Lawrence Berkeley Laboratory
• Q3.7(ii): Which element do you think would have been named by (ii) Seaborg’s group?
• Q3.7(ii): Which element do you think would have been named by (ii) Seaborg’s group?
• Q3.8: Why do elements in the same group have similar physical and chemical properties?
• Q3.8: Why do elements in the same group have similar physical and chemical properties?
• Q3.9: What does atomic radius and ionic radius really mean to you?
• Q3.9: What does atomic radius and ionic radius really mean to you?