2 What are d- block elements? Why are they called transition elements Arrange the following in increasing order of ionic stability: BeCl2, BaCl2, SrCl2, CaCl2 3 The ionic size of Cl- is greater than that of K+ though the two ions are isoelectronic. Give reason. 4 Give the IUPAC names and symbols of the elements with atomic number 101 and 107. 5 Under what conditions of T and P, most of the ideal gases deviate from their ideal gas behaviour? 6 Calculate the mass of 2.5 gram- atom of calcium. Atomic mass of calcium is 40. 7 Calculate the wavelength and frequency of a light whose period is 2.0 X 10-10 s. 8 How does Heisenberg`s uncertainty principle support concept of orbital? 9 Why electron gain enthalpies of noble gases are positive?10 A human adult breathes in approximately 0.50 L of air at 1 atm with each breathe. If an air tank holds 10 L of air at 200 atm, how many breaths the tank will supply? 11 Why is BeCl2 linear whereas SnCl2 angular molecule?12 Calculate the workdone when a gas is compressed by an average pressure o 0.50 atm so as to decrease with volume from 400 cm3 to 200 cm3. 13 Making use of the concept of hybridization discuss the shapes of (i) BeCl2 (ii) BF3 (iii) CH4 molecules 14 Give various postulates of kinetic theory of gases. 15 (a) Why air is dense at the sea level? Expalain. (b) Calculate the total pressure in a mixture of 4 g of O2 and 2 g of H2 confined to a total volume of 1L at 00C.(R= 0.0821 L atm mol-1)16 How much magnesium sulphide can be obtained from 2.00 g of magnesium and 2.00 g of sulphur by the reaction Mg + S MgS? Which is the limiting reagent? Calculate the amount of one of the reactants which remains unreacted.17 What is meant by the statement that `an electron has dual nature`? Calculate the wavelength associated with a moving electron having a kinetic energy of 1.1375 X 10-25 J. [ me = 9.1 X 10-31 kg ; h = 6.6 X10-34 Js ]18 Give the reasons of the following: 1. Fluorine has high electron gain enthalpy than chlorine. 2. Noble gases tend to be less reactive. 3. First ionization enthalpy of Mg is more than that of Na but second ionization enthalpy of Mg is less than that of Na19.Explain Bohr`s model for Hydrogen atom. Applying Bohr`s model calculate the wavelength of the radiation emitted when an electron in a hydrogen atom makes a transition from fourth energy level to first energy level. Planck`s constant = 6.63 X 10-34 J20.(a) Write outer electronic configuration of Cr atom. Why are half filled orbitals more stable? (b) State Pauli`s Exclusion Principle. (c) An electron has a velocity of 50 ms-1 accurate upto 99.99%. Calculate the uncertainty in locating its position.21.(i) Draw the shape of water molecule on the basis of VSEPR theory. (ii) Bond angle of NH3 is 1070. Why? (iii) Which bond is stronger sigma or pi and why? (iv) In BF3, B-F bond is polar but BF3 has zero dipole moment. (v) Boiling point of NH3 is higher than PH3 why?22.What are bonding and anti- bonding molecular orbitals? Describe LCAO method for their formation. What are important characteristics of these?pls can ugive me the answer for my questions as soon as posible