This is a 9th and 10th grade informational text about the lasting chemical bonds between atoms, ions, and molecules, which enable the construction of chemical compounds. While reading, students should determine the meaning of words and phrases as they are used in a text. Students should also cite strong and thorough textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text (License: https://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License).