CFT

Question What is Crystal Field Theory (CFT)? tap to flip ↻ Answer A model that explains the electronic structure and properties of transition metal complexes by considering the electrostatic interaction between metal ions and ligands. Question In CFT, what is the assumption about metal-ligand bonding? tap to flip ↻ Answer Metal-ligand bonds are purely electrostatic (ionic) in nature, with no covalent character. Question What is crystal field splitting? tap to flip ↻ Answer The splitting of degenerate d-orbitals of the metal ion into different energy levels due to the electrostatic field of ligands. Question In an octahedral complex, how do the d-orbitals split? tap to flip ↻ Answer Into two sets: $t_{2g}$ (lower energy, three orbitals: $d_{xy}$, $d_{yz}$, $d_{xz}$) and $e_g$ (higher energy, two orbitals: $d_{x^2-y^2}$, $d_{z^2}$). Question In a tetrahedral complex, how do the d-orbitals split? tap to flip ↻ Answer Into two sets: $e$ (lower energy, two orbitals: $d_{x^2-y^2}$, $d_{z^2}$) and $t_2$ (higher energy, three orbitals: $d_{xy}$, $d_{yz}$, $d_{xz}$). Question What is the crystal field splitting parameter, denoted by $\Delta_o$ or $10Dq$? tap to flip ↻ Answer The energy difference between the $t_{2g}$ and $e_g$ sets in an octahedral complex. Question What is the spectrochemical series? tap to flip ↻ Answer A series of ligands arranged in order of increasing field strength: $I^- < Br^- < S^{2-} < SCN^- < Cl^- < NO_3^- < F^- < OH^- < H_2O < NH_3 < en < NO_2^- < CN^- < CO$. Question What is a high-spin complex? tap to flip ↻ Answer A complex in which the crystal field splitting energy ($\Delta_o$) is small compared to the pairing energy, so electrons occupy higher energy orbitals before pairing up. Question What is a low-spin complex? tap to flip ↻ Answer A complex in which $\Delta_o$ is large compared to the pairing energy, so electrons pair up in lower energy orbitals before occupying higher ones. Question What is the pairing energy ($P$)? tap to flip ↻ Answer The energy required to pair two electrons in the same orbital. Question How does the magnitude of $\Delta_o$ affect the spin state? tap to flip ↻ Answer If $\Delta_o < P$, high spin; if $\Delta_o > P$, low spin. Question What is the color of a complex explained by in CFT? tap to flip ↻ Answer d-d transitions: absorption of light causes electrons to jump between split d-orbitals, and the complementary color is observed. Question What is the origin of the magnetic properties of complexes in CFT? tap to flip ↻ Answer The number of unpaired electrons in the split d-orbitals determines the magnetic moment. Question What is the formula for spin-only magnetic moment? tap to flip ↻ Answer $\mu = \sqrt{n(n+2)}$ Bohr Magnetons (BM), where $n$ is the number of unpaired electrons. Question For a $d^4$ octahedral complex, what are the possible electron configurations? tap to flip ↻ Answer High spin: $t_{2g}^3 e_g^1$ (4 unpaired); Low spin: $t_{2g}^4 e_g^0$ (2 unpaired). Question What is the crystal field stabilization energy (CFSE)? tap to flip ↻ Answer The energy stabilization gained by the metal ion due to the splitting of d-orbitals in the crystal field. Question How is CFSE calculated for an octahedral complex? tap to flip ↻ Answer $CFSE = (-0.4n_{t_{2g}} + 0.6n_{e_g})\Delta_o$, where $n$ is the number of electrons in respective orbitals. Question What is the spectrochemical series order for halide ligands? tap to flip ↻ Answer $I^- < Br^- < Cl^- < F^-$ (increasing field strength). Question Why is $CN^-$ a strong field ligand? tap to flip ↻ Answer It causes a large splitting ($\Delta_o$) due to its strong interaction with metal d-orbitals, often leading to low-spin complexes. Question What is the shape of $d_{z^2}$ orbital? tap to flip ↻ Answer A doughnut-shaped electron cloud with two lobes along the z-axis. Question Which d-orbitals point directly towards the ligands in an octahedral complex? tap to flip ↻ Answer $d_{x^2-y^2}$ and $d_{z^2}$ (the $e_g$ set). Question Which d-orbitals point between the ligands in an octahedral complex? tap to flip ↻ Answer $d_{xy}$, $d_{yz}$, $d_{xz}$ (the $t_{2g}$ set). Question What is the relation between $\Delta_t$ and $\Delta_o$? tap to flip ↻ Answer $\Delta_t = \frac{4}{9} \Delta_o$. Question Why are tetrahedral complexes usually high spin? tap to flip ↻ Answer Because $\Delta_t$ is small (only 4/9 of $\Delta_o$), so $\Delta_t < P$ typically, leading to high spin. Question What is the color of $[Cu(H_2O)_6]^{2+}$ and why? tap to flip ↻ Answer Blue, due to d-d transition absorbing red light (complementary). Question What is the magnetic moment of $[Fe(CN)_6]^{3-}$? tap to flip ↻ Answer $\mu = \sqrt{1(1+2)} = \sqrt{3} \approx 1.73$ BM (low spin, one unpaired electron). Question What is the magnetic moment of $[Fe(H_2O)_6]^{2+}$? tap to flip ↻ Answer $\mu = \sqrt{4(4+2)} = \sqrt{24} \approx 4.90$ BM (high spin, four unpaired electrons). Question What is the number of unpaired electrons in $[Co(NH_3)_6]^{3+}$? tap to flip ↻ Answer 0 (low spin, $d^6$ with $t_{2g}^6 e_g^0$). Question What is the number of unpaired electrons in $[CoF_6]^{3-}$? tap to flip ↻ Answer 4 (high spin, $d^6$ with $t_{2g}^4 e_g^2$). Question What is the CFSE for a high-spin $d^5$ octahedral complex? tap to flip ↻ Answer 0 (since $t_{2g}^3 e_g^2$: $3(-0.4\Delta_o) + 2(0.6\Delta_o) = 0$). Question What is the CFSE for a low-spin $d^5$ octahedral complex? tap to flip ↻ Answer $-2.0\Delta_o + 2P$ (since $t_{2g}^5 e_g^0$: $5(-0.4\Delta_o) + 2P = -2.0\Delta_o + 2P$). Question What is the limitation of CFT? tap to flip ↻ Answer It assumes purely ionic bonding and does not account for covalent character, and cannot explain the order of the spectrochemical series. Question What is the meaning of the term 'barycenter' in CFT? tap to flip ↻ Answer The average energy of the d-orbitals before splitting; the weighted average of split orbitals remains at the barycenter. Question For a $d^1$ octahedral complex, what is the CFSE? tap to flip ↻ Answer $-0.4\Delta_o$ (one electron in $t_{2g}$). Question For a $d^9$ octahedral complex, what is the CFSE? tap to flip ↻ Answer $-0.6\Delta_o$ (since $t_{2g}^6 e_g^3$: $6(-0.4\Delta_o) + 3(0.6\Delta_o) = -2.4\Delta_o + 1.8\Delta_o = -0.6\Delta_o$). Question What is the color of $[Ni(H_2O)_6]^{2+}$? tap to flip ↻ Answer Green, due to d-d transition. Question What is the magnetic moment of $[Mn(H_2O)_6]^{2+}$? tap to flip ↻ Answer $\mu = \sqrt{5(5+2)} = \sqrt{35} \approx 5.92$ BM (high spin, five unpaired electrons). Question What is the number of unpaired electrons in $[Cr(H_2O)_6]^{3+}$? tap to flip ↻ Answer 3 (high spin, $d^3$ with $t_{2g}^3 e_g^0$). Question What is the number of unpaired electrons in $[Mn(CN)_6]^{4-}$? tap to flip ↻ Answer 2 (low spin, $d^4$ with $t_{2g}^4 e_g^0$). Question What is the number of unpaired electrons in $[Fe(CN)_6]^{4-}$? tap to flip ↻ Answer 0 (low spin, $d^6$ with $t_{2g}^6 e_g^0$). Question What is the number of unpaired electrons in $[Co(H_2O)_6]^{2+}$? tap to flip ↻ Answer 3 (high spin, $d^7$ with $t_{2g}^5 e_g^2$). Question What is the number of unpaired electrons in $[Co(CN)_6]^{3-}$? tap to flip ↻ Answer 0 (low spin, $d^6$ with $t_{2g}^6 e_g^0$). Question What is the number of unpaired electrons in $[Ni(CN)_4]^{2-}$? tap to flip ↻ Answer 0 (square planar, $d^8$ low spin). Question What is the number of unpaired electrons in $[NiCl_4]^{2-}$? tap to flip ↻ Answer 2 (tetrahedral, $d^8$ high spin). Question What is the number of unpaired electrons in $[Cu(NH_3)_4]^{2+}$? tap to flip ↻ Answer 1 (square planar, $d^9$). Question What is the number of unpaired electrons in $[Zn(H_2O)_6]^{2+}$? tap to flip ↻ Answer 0 ($d^{10}$, no unpaired electrons). Question What is the number of unpaired electrons in $[V(H_2O)_6]^{3+}$? tap to flip ↻ Answer 2 (high spin, $d^2$ with $t_{2g}^2 e_g^0$). Question What is the number of unpaired electrons in $[Ti(H_2O)_6]^{3+}$? tap to flip ↻ Answer 1 (high spin, $d^1$ with $t_{2g}^1 e_g^0$). Question What is the number of unpaired electrons in $[Fe(H_2O)_6]^{3+}$? tap to flip ↻ Answer 5 (high spin, $d^5$ with $t_{2g}^3 e_g^2$). Question What is the number of unpaired electrons in $[Fe(CN)_6]^{3-}$? tap to flip ↻ Answer 1 (low spin, $d^5$ with $t_{2g}^5 e_g^0$). Question What is the number of unpaired electrons in $[Mn(H_2O)_6]^{2+}$? tap to flip ↻ Answer 5 (high spin, $d^5$ with $t_{2g}^3 e_g^2$). Question What is the number of unpaired electrons in $[Mn(CN)_6]^{4-}$? tap to flip ↻ Answer 3 (low spin, $d^3$ with $t_{2g}^3 e_g^0$). Question What is the number of unpaired electrons in $[Cr(CN)_6]^{3-}$? tap to flip ↻ Answer 3 (low spin, $d^3$ with $t_{2g}^3 e_g^0$). Question What is the number of unpaired electrons in $[Cr(H_2O)_6]^{2+}$? tap to flip ↻ Answer 4 (high spin, $d^4$ with $t_{2g}^3 e_g^1$). Question What is the number of unpaired electrons in $[Cr(CN)_6]^{4-}$? tap to flip ↻ Answer 2 (low spin, $d^4$ with $t_{2g}^4 e_g^0$). Question What is the number of unpaired electrons in $[CoF_6]^{3-}$? tap to flip ↻ Answer 4 (high spin, $d^6$ with $t_{2g}^4 e_g^2$). Question What is the number of unpaired electrons in $[Co(NH_3)_6]^{3+}$? tap to flip ↻ Answer 0 (low spin, $d^6$ with $t_{2g}^6 e_g^0$). Question What is the number of unpaired electrons in $[Co(H_2O)_6]^{3+}$? tap to flip ↻ Answer 0 (low spin, $d^6$ with $t_{2g}^6 e_g^0$). Question What is the number of unpaired electrons in $[Co(CN)_6]^{4-}$? tap to flip ↻ Answer 1 (low spin, $d^7$ with $t_{2g}^6 e_g^1$). Question What is the number of unpaired electrons in $[Ni(H_2O)_6]^{2+}$? tap to flip ↻ Answer 2 (high spin, $d^8$ with $t_{2g}^6 e_g^2$). Question What is the number of unpaired electrons in $[Ni(NH_3)_6]^{2+}$? tap to flip ↻ Answer 2 (high spin, $d^8$ with $t_{2g}^6 e_g^2$). Question What is the number of unpaired electrons in $[Ni(CN)_4]^{2-}$? tap to flip ↻ Answer 0 (square planar, $d^8$ low spin). Question What is the number of unpaired electrons in $[Cu(H_2O)_6]^{2+}$? tap to flip ↻ Answer 1 (octahedral, $d^9$). Question What is the number of unpaired electrons in $[Cu(CN)_4]^{3-}$? tap to flip ↻ Answer 0 (square planar, $d^8$? Actually Cu(III) is $d^8$, so 0 unpaired).

⚡ Topic Learning Kit

પર્યાવરણ પ્રકરણવિશે સમજ (ધોરણ ૩ GCERT)

Gujarati

⚡ Topic Learning Kit

ધોરણ 8 વિજ્ઞાન — ધાતુઓ, કોષ, તારાઓ અને પ્રદૂષણ (પ્રકરણ 4, 8, 17, 18)

Gujarati

⚡ Topic Learning Kit

भौतिक रसायन

Hindi