Question

Please explain this, I have no idea how to figure this out.

What molecule or polyatomic ion has the following features.
(a) four bonded atoms, no unshared electrons on the central atom
(b) two bonded atoms, no unshared electrons on the central atom
(c) two bonded atoms, one unshared pair of electrons on the central atom

Answer 1

We can't draw structures on this forum. Try this for answers.
a. CH4, CCl4, CI4, etc.
b. CO2
c. NO2^-

Here is a link for CCl4.
http://www.chemistry.ccsu.edu/crundwell/Galleries/VSEPR/ccl4.html

Here is a link to show the NO2^-.
https://www.google.com/search?q=lewis+structure+NO2^-&hl=en&client=firefox-a&hs=Se3&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=3_o4UYCUHaSF2gXO2ID4Cw&ved=0CDgQsAQ&biw=842&bih=498

Here is a link for CO2.
https://www.google.com/search?q=lewis+structure+CO2&hl=en&client=firefox-a&hs=Sd3&rls=org.mozilla:en-US:official&tbm=isch&tbo=u&source=univ&sa=X&ei=ofo4UbCCFrO02AWziIHoCA&ved=0CDAQsAQ&biw=842&bih=498

Here is a link for CCl4.