Chapter 2　 Atom Structure Exercises What is the wavelength of a neutron traveling at a speed of 3.90 km·s-1? Neutrons of these speeds are obtained from a nuclear pile. How many subshells are there in the M shell? How many orbitals are there in the f subshell? Which of the following electron configurations are possible? Explain why the others are not. (1) 1s22s12p6 (2) 1s22s22p63s13d6 (3) 1s22s22p8 (4) 1s22s12p63s23d10 Thallium has the ground-state configuration [Xe]4f145d106s26p1. Give the group and period for this element. Classify it a main-group, a d-transition, or an f-transition element. With the aid of a periodic table, arrange the following in order of increasing electrnegativity: (1) Sr, Cs, Ba (2) Ca, Ge, Ga (3) P, As, S Answers 1.The mass of the neutron, mn = 1.67×10-27 kg, therefore the wavelength of a neutron traveling at a speed of 3.90 km·s-1 is obtained by using the de Broglie relation: λ = 102 nm 2.For M shell, n = 3, so where there are 3 subshells. As l = 3 for f subshell, the number of orbitals is 2l+1 = 7. 3.All the electron configurations are possible except that one in answer (3), which allows 8 electrons filled in three 2p orbitals. 4.Thallium is a main-group element at Period 6 and Group IIIA of the periodic table. 5.(1) Cs, Ba, Sr; (2) Ca, Ga, Ge; (3) As, P, S Chapter 3 Molecular Structure Exercises Determine the hybridization state of the central atom in each of the following molecules: (a) HgCl2, (b) AlI3, and(c) PF3. Describe the hybridization process and determine the molecular geometry in each case. Use the VSEPR model to predict the geometry of the following molecules and ions: (a) AsH3, (b) OF2, (c) AlCl4‐, (d) I3‐ The N2+ ion can be prepared by bombarding the N2 molecule with fast-moving electrons. Predict the following properties of N2+: (a) electron configuration, (b) bond order, (c) magnetic character, and (d) bond length relative to the bond length of N2 (is it longer or shorter?) Which of the following can form hydrogen bonds with water? CH4, F‐，HCOOH, Na+ Answers (a) Hg is sp-hybridized， →→ (b) Al is sp2-hybridized， →→ (c) P is sp3-hybridized，→ (a) trigonal pyramidal；(b) bent；(c) tetrahedral；(d) linear (a) ；(b) 2.5； (c) paramagnetic；(d) longer bond than N2. F- and HCOOH Chapter 4 Structure of Coordination Compound Exercises Given the Ks values of [CuY]2- and [Cu(en)2]2+ are 5×1018 and 1.0×1021 respectively, try to determine which of the two complexes is more stable. Add 100mL of 0.1000mol·L-1 NaCl solution into 100mL of 0.1000mol·L-1 AgNO3 containing excessive ammonia to produce no precipitate of AgCl. Calculate the concentration of ammonia (at least) in mixture solution. Explain by calculation whether or not the precipitate AgI will form when c([Ag(CN)]2-)=c(CN-)=0.1mol·L-1 in a solution and the solid KI is added to the solution to make c(I-) equal to 0.1mol·L-1. Given the KS values of [Ag(NH3)2]+ and [Ag(CN)2]- are 1.1×107 and 1.0×1021 respectively, try to determine the direction of the following reaction. [Ag(NH3)2]+ + 2CN- [Ag(CN)2]- + 2NH3 Answers In [CuY]2- solution, [Cu2+] = x1 = 1.41×10-10mol·L-1; in [Cu(en)2]2+ solution, [Cu2+] = x2 = 2.92×10-8mol·L-1. x2>x1, [CuY]2- is more stable than [Cu(en)2]2+ [NH3] = 1.13mol·L-1 [Ag+]·[I-] = 7.69×10-21mol·L-1×0.1mol·L-1 = 7.69×10-22< Ksp(AgI) = 8.52×10-17, the precipitate AgI will not form K = 8.5×10-15, it is so smallth at the reverse reaction is spontaneous