The unit pg stands for pictogram. It is one-trillionth of a gram. Because of the very small mass, it is expressed in the prefix form of the base units for convenience. Now, the mass of cofactor a is 41.5 pg per cell. Since there are a total of 105 cells, the total mass would be:
Total mass = 105 cells * 41.5 pg/cell = 4,357.5 pg
Ionic bonds form between nonmetals and metals.
The reason ionic bonds are formed is because nonmetals and metals usually have high electronegativities, which essentially means that metals pull on nonmetals' electrons.
When a metal takes an electron from a nonmetal, the metal becomes negatively charged and the nonmetal becomes positively charged. Because opposite charges attract, the two atoms will stick together, thus forming an ionic bond
-T.B.
Convection: the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
hope that helps :)
Metals are the type of elements that are most likely to form more than one type of ion, for instance iron can form the ion of Fe^2+ or Fe^3+.