PROBLEM \(\PageIndex{1}\) Determine the formal charge and oxidation state of each element in the following: a. HCl b. CF 4 c. PCl 3 Answer a FC: H: 0, Cl: 0 OX: H: +1, Cl: -1 Answer b FC: C: 0, F: 0 OX: C: +4, F: -1 Answer c FC: P: 0, Cl: 0 OX: P: +3, Cl: -1 PROBLEM \(\PageIndex{2}\) Determine the formal charge and oxidation state of each element in the following: a. H 3 O + b. \(\ce{SO4^2-}\) c. NH 3 d. \(\ce{O2^2-}\) e. H 2 O 2 Answer a FC: H: 0, O: +1 OX: H: +1, O: -2 Answer b FC: S: +2, O: -1 OX: S: +6, O: -2 Answer c FC: N: 0, H: 0 OX: N: -3, H: +1 Answer d FC: -1 OX: -1 Answer e FC: O: 0, H: 0 OX: O: -1, H: +1 Click here to see a video of the solution PROBLEM \(\PageIndex{3}\) Calculate the formal charge and oxidation state of chlorine in the molecules Cl 2 and CCl4. Answer FC: Cl in Cl 2 : 0; Cl in CCl 4 : 0 OX: Cl in Cl 2 : 0; Cl in CCl 4 : -1 PROBLEM \(\PageIndex{4}\) Calculate the formal charge and oxidation state of each element in the following compounds and ions: a. F 2 CO b. NO – c. \(\ce{BF4-}\) d. \(\ce{SnCl3-}\) e. H 2 CCH 2 f. \(\ce{PO4^3-}\) Answer a FC: C: 0, F :0, O: 0 OX: C: +4, F: -1, O: -2 Answer b FC: N: -1, O: 0 OX: N: +1, O: -2 Answer c FC: B: -1, F: 0 OX: B: +3, F: -1 Answer d FC: Sn: -1; Cl: 0 OX: Sn: +2, Cl: -1 Answer e FC: C: 0, H: 0 OX: C: -2, H: +1 Answer f FC: P: +1, O: -1 OX: P: +5, O: -2 PROBLEM \(\PageIndex{5}\) Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in nitrosyl chloride: ClNO or ClON? Answer ClNO Click here to see a video of the solution PROBLEM \(\PageIndex{6}\) Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in hypochlorous acid: HOCl or OClH? Answer HOCl PROBLEM \(\PageIndex{7}\) Based on formal charge considerations, which of the following would likely be the correct arrangement of atoms in sulfur dioxide: OSO or SOO? Answer OSO Click here to see a video of the solution PROBLEM \(\PageIndex{8}\) Draw the structure of hydroxylamine, H 3 NO, and assign formal charges; look up the structure. Is the actual structure consistent with the formal charges? Answer The structure that gives zero formal charges is consistent with the actual structure: PROBLEM \(\PageIndex{9}\) Which of the following structures would we expect for nitrous acid? Determine the formal charges: Answer The first structure is the best structure. the formal charges are closest to 0 (and also the second structure does not give a complete octet on N) Have a video solution request? Let your professors know here. ***Please know that you are helping future students - videos will be made in time for next term's class. Feedback Think one of the answers above is wrong? Let us know here .