Knewtons Exam 3 Questions With Verified Answers

Knewtons Exam 3 Questions With Verified Answers. Which of the following is very reactive and can readily combine with molecules containing atoms with lone pairs? hyperv alent molecues odd-electron molecules electron -deficient molecules all of the above - answer✔✔electron -deficient molecules Electron -deficient molecules that do not have filled valence shells can readily combine with molecules containing atoms with lone pairs. When drawing a Lewis structure for a free radical, which type of atom is more likely to receive the unpaired electron? the more electronegative element the less electronegative element the heavier element the lighter element - answer✔✔the less electronegative element A more electronegative element is more likely to be surrounded by more electrons and fulfill its octet. A less electronegative element is more likely to have the electron deficiency, in this case the unpaired electron. Recall that free radicals are electron deficient and display the same stability trends as electron deficient cations, like carbocations. A sul fur atom can make up to ____ bonds in a Lewis structure. - answer✔✔6 With six valence electrons, sulfur can make a maximum of six bonds. Which of the following elements can NOT form hypervalent molecules? (select all that apply) N S Br B - answer✔✔N, B Elements in the second period of the periodic table (n=2) can accommodate only eight electrons in their valence shell orbitals because they have only four valence orbitals (one 2s and three 2p orbitals). Elements in the third and higher periods (n≥3) have more than four valence orbitals and can share more than four pairs of electrons with other atoms because they have empty d orbitals in the same shell. Therefore, of the elements listed above boron and nitrogen can not form hypervalent molecules which molec ule is NOT hypervalent? SF6 PBr3 PBr5 XeF6 - answer✔✔PBr3 Phosphorus can make hypervalent compounds, but in this specific example it is sharing three bonds and has one lone pair, so it has simply a full octet. SF6 has a sulfur atom surrounded by 6 fluorine atoms, PBr5 has a phosphorous atom surrounded by 5 bromin e atoms, and XeF6 has a xenon atom surrounded by 6 fluorine atoms, all of which are hypervalent because there are more than four pairs of shared electrons around the central atom. Hypervalent molecules require that central atoms access: s orbitals p orbit als d orbitals all of the above - answer✔✔all of the above All of the above orbitals are required if a central atom hopes to make more than four bonds to other atoms. In a Lewis structure involving bromine and chlorine, if a central bromine atom has two lone pairs, how many chlorine atoms must be present? - answer✔✔3 Cl atoms If there are two lone pairs, that means four of bromine's seven valence electrons are occupied. That leaves three available for covalent bonds to three chlorine atoms. Which of the following is true? The overall formal charge in a molecule will always equal 1. An atom's formal charge is always equal to its actual charge. In covalent molecules, formal charges are hypothetical. all of the above - answer✔✔In covalent molecules, formal charges are hypothetical. In a molecule or ion containing only covalent bonds, the formal charge of an atom is the hypothetical charge that the atom would have if electrons could be redistributed evenly between atoms. In neutral covalent molecules, formal charges are always a formality —each of the atoms contained therein are electrically neutral. Conversely, in covalently bonded ions (which carry an overall charge), the formal charge of a given atom may be the actual charge on the atom, but often is not. On the resonance hybrid for NO2 -, in between the nitrogen atom and each oxygen atom there is: one covalent bond one covalent bond and one partial bond two covalent bonds two partial bonds - answer✔✔one covalent bond and one partial bond