"A formula that shows the kinds and numbers of atoms in the smallest representative unit that a substance"

While a formula unit is described as :

The lowest entirety number ratio of ions in one ionic compound. For this reason the formula unit for sodium chloride is NaCl.

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Though the meanings seem come differ, the written formulas appear identical. A chemical formula appears to it is in another means to stand for a formula unit. For example, NaCl is both the chemical formula and formula unit for salt Chloride. Is there ever a difference between the composed terms?

ionic-compounds terminology
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edited jan 11 "17 at 14:39
asked january 9 "17 in ~ 19:13

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Molecular compound such as water exist as discrete particles, molecules. This is due to the forming of covalent bonds where each atom has a particular partner come which that is bonded. Every molecule of water contains one atom of oxygen and also two atom of hydrogen. So, H2O is the formula. This have the right to be more specifically referred to as a molecule formula.

In ionic compounds such as table salt, NaCl, the atom (as ions) do not link to details neighbors. Bordering each chloride ion in a salt crystal are six sodium ions. Likewise, six chloride ion surround each salt ion. This attraction of oppositely charged ion extends throughout the entire crystal. There is no discrete bonding of a specific sodium ion come a details chloride ion. So the formula for sodium chloride is expressed as the smallest entirety number ratio in between the Na and Cl ions which is 1:1 for sodium chloride. So, NaCl is likewise a formula yet not a molecule formula.

The factor for the ax "formula unit" is that it is useful when we talk about how much of one problem is forced to integrate with a specific amount of an additional substance. For example: to make the smallest amount of hydrogen lead carbonate we integrate one molecule that water v one molecule that carbon dioxide.

But currently suppose we desire to integrate silver nitrate v sodium chloride. Both that these room ionic compounds, they perform not form molecules. In this case you would certainly say the one formula unit (FU) of sodium chloride combines through one FU of silver nitrate.

See more: The Likelihood That A Particular Event Will Occur, Probability Of An Event

The one-to-one combine in both these instances is merely coincidence. It might take 3 FUs of substance A to incorporate exactly through 2 FUs of substance B in a different example.