Fuel cells are used in many areas, such as the aerospace industry, where energy efficiency is more important than high power output. One fuel cell uses methanol, CH3OH, as a fuel. Predict the ideal bond angle for each of the following: a. H―C―H
b. H―C―O
c. C―O―H.

Within a molecule, the bond angle refers to the angle found between the central atom and its bonded atoms. The total number of bonded atoms and the unshared pairs of electrons within a molecule is the number of electron domains.  

By considering the Lewis formula for methanol it is witnessed that the central carbon atom comprises no unshared pair of electrons and four bonded atoms. Therefore, 4 is the number of electron domains present around the carbon atom, so the bond angle present in the given case will be 109.5 degrees. Thus, the bond angles of H-C-O and H-C-H will equivalent to 109.5 degrees.  

There are two unshared pairs of electrons and two bonded atoms around the central oxygen atom. Therefore, 4 will be the number of electron domains around the atom of oxygen. Thus, a 109.5 degree will be the bond angle found on it, and therefore, the bond angle of C-O-H will also be equivalent to a 109.5 degree. Hence, in the methanol, CH3OH, the bond angles of H-C-H, C-O-H, and H-C-O will be 109.5 degrees.  

tracks, burrows, eggshells, nests, tooth marks, or gastroliths

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."