Refer to a modern periodic table for the relative atomic mass of magnesium () and chlorine ():
: .
: .
In other words, the mass of of atoms would be (approximately) .
Likewise, the mass of of atoms would be approximately .
One formula unit of the ionic compound includes exactly as many atoms as there are in the given formula. The formula mass of a compound is the mass of of the formula units of this compound.
The formula includes one atom and two atoms.
Hence, every formula unit of would include the same number of atoms: one atom and two atoms. There would be of atoms and of atoms in of formula units.
Thus, the mass of of formula units would be equal to the mass of of atoms plus the mass of of atoms. (The mass of of each atom could be found from the relative atomic mass of each element.)
.
In other words, the formula mass of is .
Therefore, the number of formula units in of would be:
.
Multiple by Avogadro's Number to estimate the number of formula units in :
Hydrogen bonding occurs when a hydrogen atom is covalently bonded to an NN, OO, or FF atom.
A hydrogen atom acquires a partial positive charge when it is covalently bonded to an FF atom.
A hydrogen bond is possible with only certain hydrogen-containing compounds.
Explanation:
A hydrogen bond does not occur in all hydrogen containing compounds. Hydrogen bonds only occur in those compounds where hydrogen is bonded to a highly electronegative element such as fluorine, oxygen or nitrogen.
In a hydrogen bonded specie, hydrogen acquires a partial positive charge and the electronegative element acquires a partial negative charge which extends throughout the molecule.
Gold is an element. Water is made from hydrogen and oxygen, and silicon dioxide is an oxide of silicon, consisting of <span> two oxygen atoms and one silicon</span>