Hello I'm stuck on a few problems in chemistry and I couldn't find the answers in the book or on the internet so hopefully some of you could help me 1. If there are no non-bonding pairs of electrons in the outer shell of an atom, its covalent bonds will be ______ A. As close together as possible B. As far apart as possible C. Arranged symmetrically D. Both b and c 2. Multiple bonds also play a part in determining molecular shape. The triple bond always aligns the other bonds on these atoms ____ A. At right angles B. Into different planes C. Trigonal planar D. Trigonal pyramidal 3. Why can any atom have no more than eight valence electrons? I put because it is most stable with eight...but I'm not sure if it is enough detail so feel free to add or correct it. 4. Are there exceptions to the general valence electron rule? Why does these exceptions occur? Obviously yes but I can't explain it....(talking about d and f orbitals) Also I need help on these but I can see if you don't wanna help me on these as they are more work but... Give the valence electrons for each atom, and the total...and draw the Lewis Electron Dot Structure for each. OH 1- H3O 1+ NH4 1+ SO4 2- I'm not really sure how to do those with charges... Thanks a lot and plus rep for all who help me. =]
number 3 i can't really put this into an answer but i can explain it. Atoms can only hold 8 electrons per shell and they fill up to eight before going to the next outer shell. They keep filling up to 8 electrons until theres an odd number. (Atom)8]8]8]8]4]
1. D. steric interaction between any local electrons would result in bonds forming at the furthest possible from each other I think. not sure on the exact angle, it depends on how many substituents and lone pairs on said molecule. 2. should be linear.. trigonal planar is the closest. usually in a triple bond the angles are 180. 3/4. s and p orbitals hold 6, 2s and 6p. I think metals, with d and f orbitals, use 5 and 7 orbitals to hold 10 and 14 valence electrons instead of 4 s/p orbitals. look up metal valence electrons.. 5. OH- .. 6+1 + one negative charge, ie one extra electron. we call these anions. put 6 around O and 1 on H.. thus you have 5 on O, ie an unpaired electron, that's where that -1 goes. I'm surprised your book hasn't helped you with this
Thanks for the help...you're right on number 2 it was linear...got the answers mixed up. The thing about the book is it shows very basic examples and then when I get to the actual work it is way more advanced than what the book shows...so I have no good examples to go by...plus rep when I can though.
1. If there are no non-bonding pairs of electrons in the outer shell of an atom, its covalent bonds will be ______ A. As close together as possible B. As far apart as possible C. Arranged symmetrically D. Both b and c Shit don't like to be next to each other...simple sterics on this one. Try holding four balloons together by their knot between your thumb and index finger...and observe. 2. Multiple bonds also play a part in determining molecular shape. The triple bond always aligns the other bonds on these atoms ____ A. At right angles B. Into different planes C. Trigonal planar D. Trigonal pyramidal None of the above. Triple bonds make 180 degrees (linear) from the other substituent. Look up acetylene (ethyne) as an example. 3. Why can any atom have no more than eight valence electrons? s-orbitals hold 2, p-orbitals hold 6 electrons...and since these are the most common valence orbitals they total to 8 electrons. 4. Are there exceptions to the general valence electron rule? Why does these exceptions occur? simply put, d-orbitals. They are perfectly capable of sharing electrons just like s- and p-orbitals. Also I need help on these but I can see if you don't wanna help me on these as they are more work but... Give the valence electrons for each atom, and the total...and draw the Lewis Electron Dot Structure for each. OH 1- H3O 1+ NH4 1+ SO4 2- I'm not really sure how to do those with charges... Don't worry about the charges...just draw the first three so that they satisfy the octet rule around the central atom (O, O and N, respectively) and the formal charges will take care of themselves. In all three cases, just draw the central atom with four pairs of electrons around them, and then add the necessary number of hydrogens (1, 3 and 4), each of which will share a pair of electrons with the central atom. For SO4, it's a little trickier because sulfurs have d-orbitals. The sulfur will double bond two oxygen atoms and single bond two oxygens. The two oxygen atoms that are double bonded have the appropriate number of electrons appropriated to them (6) so their formal charge is 0, while the singly bonded oxygen atoms have 7 electrons appropriated to them so that they each have a formal charge of -1...giving a net -2 charge. Hope that is of some help.
chiefton, the charges on the molecules just denotes the charge at the natural state.... so you nailed it