Question #d5404

1 Answer
Oct 26, 2015

For ionic bonds: You should familiarize yourself with the common oxidation states of the elements.

For covalent bonds: Know the number of valence electrons.

Explanation:

There really is no shortcut.

For ionic bonds (which is mostly a bond between metal and nonmetal), you can either memorize the most common oxidation states or you can utilize the table below as your guide.
http://www.drcruzan.com/OxidationNumbers.html

The rule for ionic bonds is to "exchange the superscripts for the subscripts".

For example:

#Be^"2+"# #Cl^-1# = #BeCl_2#

#H^+# #O^"2-"# = #H_2O#

#K^+# #SO_4^"2-"# = #K_2SO_4#

#Al^"3+"# #SO_4^"2-"# = #Al_2(SO_4)_3#

For covalent bonds, it's a bit tricky since you have to know the number of valence electrons plus the elements can share at most six electrons between them.