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In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.
The electronic configuration of the element which is just above the element with atomic number 43 in the same group is ______.
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Which of the following sets contain only isoelectronic ions?
(i) \[\ce{Zn^{2+}, Ca^{2+}, Ga^{3+}, Al^{3+}}\]
(ii) \[\ce{K+ , Ca^{2+}, Sc^{3+}, Cl-}\]
(iii) \[\ce{P^{3-}, S^{2-}, Cl- , K+}\]
(iv) \[\ce{Ti^{4+}, Ar, Cr^{3+}, V^{5+}}\]
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An element belongs to 3rd period and group-13 of the periodic table. Which of the following properties will be shown by the element?
(i) Good conductor of electricity
(ii) Liquid, metallic
(iii) Solid, metallic
(iv) Solid, non metallic
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Identify the group and valency of the element having atomic number 119. Also predict the outermost electronic configuration and write the general formula of its oxide.
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How would you explain the fact that first ionisation enthalpy of sodium is lower than that of magnesium but its second ionisation enthalpy is higher than that of magnesium?
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How does the metallic and non-metallic character vary on moving from left to right in a period?
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Justify the given statement with suitable examples— “the Properties of the elements are a periodic function of their atomic numbers”.
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Write down the outermost electronic configuration of alkali metals. How will you justify their placement in group 1 of the periodic table?
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Use the information and data given below:
• Boiling point of \[\ce{HF, HCl, HBr and HI}\] are 293 K, 189 K, 206 K and 238 K respectively.
Why is boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?
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Thermodynamics is not concerned about ______.
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Thermodynamics mainly deals with:
(i) interrelation of various forms of energy and their transformation from one form to another.
(ii) energy changes in the processes which depend only on initial and final states of the microscopic systems containing a few molecules.
(iii) how and at what rate these energy transformations are carried out.
(iv) the system in equilibrium state or moving from one equilibrium state to another equilibrium state.
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Consider the following reaction between zinc and oxygen and choose the correct options out of the options given below:
\[\ce{2 Zn (s) + O2 (g) -> 2 ZnO (s); ∆H = - 693.8 kJ mol^{-1}}\]
(i) The enthalpy of two moles of \[\ce{ZnO}\] is less than the total enthalpy of two moles of \[\ce{Zn}\] and one mole of oxygen by 693.8 kJ.
(ii) The enthalpy of two moles of \[\ce{ZnO}\] is more than the total enthalpy of two moles of \[\ce{Zn}\] and one mole of oxygen by 693.8 kJ.
(iii) 693.8 kJ mol–1 energy is evolved in the reaction.
(iv) 693.8 kJ mol–1 energy is absorbed in the reaction.
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Which of the following is not an example of redox reaction?
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Identify disproportionation reaction
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Which of the following elements does not show disproportionation tendency?
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Which of the following statement(s) is/are not true about the following decomposition reaction.
\[\ce{2KClO3 -> 2KCl + 3O2}\]
(i) Potassium is undergoing oxidation.
(ii) Chlorine is undergoing oxidation.
(iii) Oxygen is reduced.
(iv) None of the species are undergoing oxidation or reduction.
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Identify the correct statements with reference to the given reaction.
\[\ce{P4 + 3OH- + 3H2O -> PH3 + 3H2PO^{-}2}\]
(i) Phosphorus is undergoing reduction only.
(ii) Phosphorus is undergoing oxidation only.
(iii) Phosphorus is undergoing oxidation as well as reduction.
(iv) Hydrogen is undergoing neither oxidation nor reduction.
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\[\ce{MnO^{2-}4}\] undergoes disproportionation reaction in acidic medium but \[\ce{MnO^{-}4}\] does not. Give reason.
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Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.
Reason (R): The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in \[\ce{O2}\] and –2 oxidation state in \[\ce{H2O}\].
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Assertion (A): Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.
Reason (R): In the representation \[\ce{E^Θ_{Fe^{3+}/Fe^{2+}}}\] and \[\ce{E^Θ_{Cu^{2+}/Cu}, Fe^{3+}/Fe^{2+}}\] and \[\ce{Cu^{2+}/Cu}\] are redox couples.
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