Title DPP-1 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 1 1 (c) Isoelectronic species have same number of electron. Mg 2+ and Na + both have 10 electrons hence, they are isoelectronic species. 2 (c) This is obtained by the solution of Schrodinger wave equation Probability = Ψ2dV Ist orbital is spherically symmetrical ∴ V = 4 3 πr 3 , ∴ dV dr = 4πr 2 ∵ Probability = Ψ2 4πr 2dr 4 (a) ∆E (eV) = 12375 λin Å = 12375 5890 = 2.10 eV 5 (b) 1 eV = 1.602 × 10―12erg. 6 (b) s can have only two values +1/2 and ―1/2. 7 (c) The de-Broglie wavelength associated with the charged particle as For electron, λ = 12.27 V Å For proton, λ = 0.286 V Å For α-particles, λ = 0.101 V Å 8 (b) λ = h mv = 6.63 × 10―34 1.67 × 10―27 × 1 × 103 = 3.97 × 10―10m~0.40 nm. 9 (b) The number of waves in an orbit=n. Topic :- STRUCTURE OF ATOM Solutions
10 (a) E ∝ ( 1 n 2 1 ― 1 n 2 2 ) or E ∝ 1 n 2 11 (b) n is an integer except zero. 12 (c) According to aufbau principle, electrons enter into orbitals according to their energy. The electrons first enters into orbital having lesser value of (n + l). If the value of n + l is same for two orbitals then the electron will first enter into orbital having lesser value of n. n = 5, l = 0 ∴ n + l = 5 + 0 = 5 For other, n = 3, l = 2 ∴ n + l = 3 + 2 = 5 ∵ Both of the orbitals have same value for n + l. ∴ Electron will enter into orbital having lower value of n. ∴ Electron will enter into n = 3, l = 2 orbital. 13 (b) E = hc λ ,h and c for both causes are same so, E1 E2 = λ2 λ1 = 16000 8000 E1 = 2E2 14 (c) When n = 3, number of values of l are 0 to (n ― 1)i.e., 0, 1, 2 Hence, when n = 3, then l = 3 does not exist. 15 (c) We know that, ∆E = hc.R[ 1 n 2 1 ― 1 n 2 2 ] For lowest energy, of the spectral line in Lyman series, n1 = 1, n2 = 2 Hence, ∆E = hc.R[ 1 1 2 ― 1 2 2] ∆E = 3hcR 4 16 (c) Cathode rays are fastly moving electrons. 17 (c) 1. n = 4, l = 0, m = 0,s = + 1 2
→4s energy level. 2. n = 3, l = 1, m = ―1, s = + 1 2 →3p energy level. 3. n = 3, l = 2, m = ―2, s = + 1 2 →3d energy level. 4. n = 3, l = 0, m = 0, s = + 1 2 →3s energy level. According to aufbau principle, the energy of orbitals (other than H-atom) depend upon n + 1 value. n + l for 3d = 3 + 2 = 5 So, it is highest energy level (in the given options). 18 (d) Each one possesses mass. 19 (c) X-rays have larger wavelength than γ-rays. 20 (c) ΔE = hc λ