Micoscale Reactions Explorer Blog

• Draw a Lewis structure for an ionic bond between potassium and iodine.  Draw a Lewis structure for an ionic bond between lead(II) and iodine. Why do they differ?

• [K]+1 [I]-1
• [Pb(II)]+2 [I]2^-2

These differ because when potassium and iodine are combined they are neutral, meaning they have balanced charges. Lead (II) and iodine however,are not balanced and an another idoine atom must be added in order for the elements to be neutral.

• What determines the formula in an ionic compound? (including: what determines the number of ions needed, how do you know how many ions you have in a compound, and why is the formula in that order?)

 The elements charge determines the formula in an ionic compound. The charge can easily be determined by the number of valence electrons the atom gains or loses. The ions are shown in the formula as capital letters,underneath these letters are numbers called subscripts which tell how many there are. The parentheses are an identification that a subscript applies to more than one element in the compound formula. In any compound,the cation (+) is always written before the anion  (-) 

• How are ionic compounds named?  Provide examples.

In order to name an ionic compound first you must identify which element have cations and anions. Then you can use one of two methods,the criss cross method or setting the cation and anions equal to zero. I set the ions equal to zero and if they are neutral than you don't have to change (multiply,add,etc.) the element. If no changes are made there will most likely be no subscripts. If there are changes then,for example,whatever you multiply the ion by will be the subscript of that element. But always keep in mind that cations ALWAYS come first in an ionic compound.

Some examples are:

• Cu(OH)2= Copper(II) Hydroxide
• MgCO3= Magnesium Carbonate
• AgCl= Silver Chloride