Calculate the formal charge on each atom from valence electrons, non-bonding electrons and half the bonding electrons, and use it to select the preferred Lewis formula among alternatives, choosing the one with charges closest to zero.
Tę umiejętność sprawdza 18 zadań wzorowanych na arkuszach IB z lat 2022–2026.
(i) Sulfur dioxide is oxidized to sulfur trioxide by nitrogen dioxide in the atmosphere. Determine the enthalpy change, ΔH⊖, in kJ mol−1, for the reaction SO2(g) + NO2(g) → SO3(g) + NO(g) given these reactions and enthalpy…
The Lewis formula of the chlorate(VII) ion, ClO4−, can be drawn with four single Cl–O bonds, as shown. What is the formal charge of the chlorine atom in this Lewis formula? A. −1 B. +1 C. +3 D. +7
The cyanate ion, NCO−, can be represented by two Lewis formulas, X and Y. Which row correctly gives the formal charges on N, C and O in each structure and identifies the more stable structure? A. X: 0, 0, −1; Y: −1, 0, 0; more stable: Y B. X: 0, 0, −1;…
Sulfurous acid has the formula H2SO3. (i) Using the concept of formal charge, outline why Lewis formula 2 is the more stable, preferred structure. (ii) Write the formula for the conjugate base formed from sulfurous acid.
Which Lewis formula of the sulfate ion, SO42−, is preferred on the basis of formal charges? A. Formula A B. Formula B C. Formula C D. Formula D
Formal charges can be used to choose between possible Lewis structures for the cyanate ion, NCO−. Which structure is preferred? Non-bonding pairs are not shown; each atom has a complete octet. A. [N=C=O]− B. [N≡C−O]− C. [N−C≡O]−…
(i) Draw a Lewis (electron dot) structure of the nitrite ion. (ii) Deduce the formal charges of the nitrogen atom and of both oxygen atoms, and add them to the structure you drew in (i). (iii) Predict the shape of the ion and the size of the O-N-O bond angle.…
Element E forms the oxoanion EO43−. Two possible Lewis structures of the ion are shown, with lone pairs drawn as dots. (i) Use formal charges to show which of the two structures is the better representation of the ion. (ii) The oxide E4O10…
Sulfur dioxide, SO2, can be represented by more than one Lewis (electron dot) structure. (i) Sketch two different Lewis (electron dot) structures of SO2, one in which all atoms obey the octet rule and one in which sulfur does not. (ii) State the…
Bromine radicals form when the bond in a bromine molecule is broken by ultraviolet light. The energy needed to break the bond in one molecule of Br2 is 3.21 × 10−19 J. (i) Calculate the minimum frequency of light needed to break this…
The Lewis formula of the cyanate ion is shown below. What are the formal charges on the atoms in this ion? The options list the formal charges on O, C and N in that order. A. O: 0, C: 0, N: −1 B. O: −1, C: +1, N: −1 C. O: 0, C: −1, N: 0 D. O: −1, C: 0, N: 0
Which is the preferred Lewis structure of the phosphate ion, PO43−, based on formal charge? A. Structure A B. Structure B C. Structure C D. Structure D
Which Lewis structure of SO2Cl2 is preferred on the basis of formal charges? A. Diagram A B. Diagram B C. Diagram C D. Diagram D
Which Lewis formula of the perchlorate ion, ClO4−, is preferred on the basis of the lowest formal charges? A. Four Cl–O single bonds B. One Cl=O double bond and three Cl–O single bonds C. Two Cl=O double bonds and two Cl–O single bonds D. Three Cl=O…
Ozone, O3, is an allotrope of oxygen found in the upper atmosphere. (i) Complete the boxes with arrows to show the ground-state electron configuration of an oxygen atom. (ii) Deduce a Lewis (electron dot) structure of O3 in which every atom has…
What is the formal charge of the boron atom in the tetrafluoroborate ion, BF4−, in which boron is bonded to each of four fluorine atoms by a single bond? A. −3 B. −1 C. 0 D. +1
Solid ammonium chloride decomposes when heated to form two gases, ammonia and hydrogen chloride. (i) Write the chemical equation for this decomposition. (ii) Calculate the volume of ammonia produced at STP when an 8.00 g sample of ammonium chloride decomposes.…
Deduce the Lewis (electron dot) structure of sulfur trioxide.
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