We're going to be honest: we do Physics. That's why this is called The Physics Classroom website. And when we do the Teacher's Notes section for our Concept Builders, we typically have a lot to say ... and a lot of resources to point you to. We're not claiming to be ignorant of chemistry; we just don't have a lot of resources here at The Physics Classroom to point you to. And so this page is going to be a lot shorter than our usual page that accompanies our Physics Concept Builders. That's our honest confession.

Most Chemistry courses give attention to the topic of the bonding of atoms to form molecules. The discussion usually centers around a contrast of two common types of bonding - covalent bonding and ionic bonding. This Concept Builder provides a heavily logic-based exercise in how and why atoms of different elements would undergo ionic bonding. Much of the Concept Builder is reliant upon a representation known as the electron shell diagram. Electron shell diagrams show electrons positioned in the various electron shells surrounding the nucleus of the atom. They are useful tools for identifying the number of valence electrons present in the outer shell of the atom and predicting whether the atom would be more likely to gain or lose electrons in order to satisfy the octet rule.

There are three different scaffolded activities in this Concept Builder. The activities are developmental in nature, leading incrementally to an understanding of ionic bonds forming between atoms of metal and nonmetal elements by the transfer of electrons. We recommend the use of all three activities in order for students to internalize a complete understanding of the topic. The three activities in this Concept Builder are differentiated as follows:
 

• Identify the Ionic Bond: Question Groups 1-4 ... Students are presented with four pairs of elements and asked which two pairs of elements would be involved in ionic bonding.
• Ion Formation: Question Groups 5-8 ... Students create an electron shell diagram for a given element and then decide on whether the element would gain or lose electrons to become an ion and how many electrons would be gained or lost. They must also state the charge of the ion that is formed.
• Electron Transfer: Question Groups 9-14 ... Students are given two elements - a metal and a nonmetal - and must make complete five tasks: identify the electron shell diagram; state which element would form a cation and an anion; state how many electrons are gained or lost in the process of becoming an ion; identify the numbers of each ion that would combine to form an ionic compound; and identify the formula of the ionic compound.

There are a total of 38 1uestions in the Concept Builder. The questions can be viewed on a separate page.

Like all our Concept Builders, this Concept Builder utilizes a variety of strategies to make each student's experience different. The ordering of questions is random. The Question number assigned to each question is scrambled. For instance, two side-by-side students will not have the same question for question number three. And questions are organized into "groups" with questions within the same group being very similar (for instance, they have the same type of chemical compounds) but not identical.

The Concept Builder also keeps track of student progress. It requires that students demonstrate a mastery of questions in each Question Group. If they miss a question from one group, then they will have to answer two consecutive questions correctly in order to demonstrate mastery. Progress is displayed in the progress report on the right side of the Concept Builder. A star indicates a demonstration of mastery. A question with a red background indicates that the student has missed the question. And a question with a yellow background means that the student must get one more question from that Question Group correctly answered in order to obtain a star. When an activity is completed, the student will be awarded a Trophy. This Trophy is displayed on the Main Menu screen. These strategies make the Concept Builder an ideal addition to the 1:1 classroom and other settings in which computers are readily available. 


In order to complete an activity, a student must correctly analyze each question of that difficulty level. If a student's analysis is incorrect, then the student will have to correctly analyze the same or very similar question twice in order to successfully complete the activity. This approach provides the student extra practice on questions for which they exhibited difficulty. As a student progresses through an activity, a system of stars and other indicators are used to indicate progress on the activity. A star is an indicator of correctly analyzing the question. Once a star is earned, that question is removed from the que of questions to be analyzed. Each situation is color-coded with either a yellow or a red box. A red box indicates that the student has incorrectly analyzed the question and will have to correctly analyze it twice before earning a star. A yellow box is an indicator that the question must be correctly analyzed one time in order to earn a star. Once every question of a difficulty level has been analyzed, the student earns a Trophy which is displayed on the Main Menu. This system of stars and trophies allows a teacher to easily check-off student progress or offer credit for completing assigned difficulty levels.

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise.