ALEX Learning Activity


How Do Compounds Combine?

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  This learning activity provided by:  
System:Andalusia City
School:Andalusia City Board Of Education
  General Activity Information  
Activity ID: 2212
How Do Compounds Combine?
Digital Tool/Resource:
How Do Compounds Combine?
Web Address – URL:

This activity should be used as an Engage activity.  The students will recall a jigsaw puzzle has pieces that connect in a certain way.  Each piece of the puzzle is unique. The pieces fit together by sharing tabs with other pieces.  Once the puzzle has been completed, it looks very different from all the pieces that were used to create it.  Like the pieces of a puzzle, atoms can join together and form a compound by sharing electrons. 

This activity results from the ALEX Resource Development Summit. 

  Associated Standards and Objectives  
Content Standard(s):
SC2015 (2015)
Grade: 8
Physical Science
1 ) Analyze patterns within the periodic table to construct models (e.g., molecular-level models, including drawings; computer representations) that illustrate the structure, composition, and characteristics of atoms and molecules.

NAEP Framework
NAEP Statement::
P12.2: Electrons, protons, and neutrons are parts of the atom and have measurable properties, including mass and, in the case of protons and electrons, charge. The nuclei of atoms are composed of protons and neutrons. A kind of force that is only evident at nuclear distances holds the particles of the nucleus together against the electrical repulsion between the protons.

NAEP Statement::
P12.3: In the Periodic Table, elements are arranged according to the number of protons (called the atomic number). This organization illustrates commonality and patterns of physical and chemical properties among the elements.

NAEP Statement::
P8.3a: All substances are composed of 1 or more of approximately 100 elements.

NAEP Statement::
P8.3b: The periodic table organizes the elements into families of elements with similar properties.

NAEP Statement::
P8.4a: Elements are a class of substances composed of a single kind of atom.

NAEP Statement::
P8.4b: Compounds are composed of two or more different elements.

NAEP Statement::
P8.5b: Metals and acids are examples of such classes.

NAEP Statement::
P8.5c: Metals are a class of elements that exhibit common physical properties such as conductivity and common chemical properties such as reacting with nonmetals to produce salts.

Unpacked Content
Scientific And Engineering Practices:
Developing and Using Models
Crosscutting Concepts: Patterns
Disciplinary Core Idea: Matter and Its Interactions
Evidence Of Student Attainment:
  • Analyze patterns within the periodic table.
  • Construct models that illustrate the structure, composition, and characteristics of atoms.
  • Construct models that illustrate the structure, composition, and characteristics of molecules.
Teacher Vocabulary:
  • Element
  • Atom
  • Protons
  • Nucleus
  • Electrons
  • Neutrons
  • Atomic number
  • Periodic table
  • Array
  • Atomic mass
  • Period
  • Group
  • Chemical properties
  • Physical properties
  • Molecule
  • Bond
  • Chemical bond
  • Valence electron
  • Ion
  • Ionic bond
  • Nonmetal
  • Metal
  • Covalent bond
  • Metallic bond
  • Conductivity
Students know:
  • Elements are substances composed of only one type of atom each having an identical number of protons in each nucleus.
  • Atoms are the basic units of matter and the defining structure of elements.
  • Atoms are made up of three particles: protons, neutrons and electrons.
  • The number of protons in an atom's nucleus is equal to the atomic number.
  • The periodic table arranges all the known elements in an informative array.
  • Elements are arranged left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.
  • Rows in the periodic table are called periods. As one moves from left to right in a given period, the chemical properties of the elements slowly change.
  • Columns in the periodic table are called groups. Elements in a given group in the periodic table share many similar chemical and physical properties.
  • The period number of an element signifies the highest energy level an electron in that element occupies (in the unexcited state). The number of electrons in a period increases as one traverses down the periodic table; therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases.
  • A molecule is formed when two or more atoms bond together chemically.
  • A chemical bond is the result of different behaviors of the outermost or valence electrons of atoms.
  • Ionic bonds are the result of an attraction between ions that have opposite charges. Ionic bonds usually form between metals and nonmetals; elements that participate in ionic bonds are often from opposite ends of the periodic table. One example of a molecule that contains an ionic bond is table salt, NaCl.
  • Covalent bonds form when electrons are shared between atoms rather than transferred from one atom to another. The two bonds in a molecule of carbon dioxide, CO2, are covalent bonds.
  • Metallic bonds exist only in metals, such as aluminum, gold, copper, and iron. In metals, each atom is bonded to several other metal atoms, and their electrons are free to move throughout the metal structure. This special situation is responsible for the unique properties of metals, such as their high conductivity.
Students are able to:
  • Analyze patterns within the periodic table to construct models of atomic and molecular structure, composition, and characteristics.
  • Identify the relevant components of the atomic and molecular models.
  • Describe relationships between components of the atomic and molecular models.
Students understand that:
  • Patterns in the periodic table predict characteristic properties of elements. These trends exist because of the similar atomic structure of the elements within their respective group families or periods, and because of the periodic nature of the elements.
  • The structure, composition, and characteristics of atoms and molecules are dependent upon their position in the periodic table.
AMSTI Resources:
AMSTI Module:
Experimenting with Mixtures, Compounds, and Elements

Alabama Alternate Achievement Standards
AAS Standard:
SCI.AAS.8.1- Identify parts of an atom (i.e. protons, neutrons, electrons); recognize that the periodic table is organized to show patterns of common traits of elements; locate metals and nonmetals on the periodic table.

Learning Objectives:

I can recognize atoms form a compound by sharing electrons.

  Strategies, Preparations and Variations  

  1. Explain to students that they will be working against the clock to put a jigsaw puzzle together.
  2. Divide the students into groups of 2-4 to put a jigsaw puzzle together.
  3. Distribute the jigsaw puzzles.
  4. Set the timer and begin.
  5. The teacher will circulate around the room to make sure all groups are on task.
  6. Stop the timer once there is a winning group, but allow all the groups to complete their puzzles.
  7. Once all the puzzles have been completed, discuss with the students how the finished puzzle looks very different from all the pieces that were used to create it.
  8. Like the pieces of a puzzle, atoms can join together and form a compound by sharing electrons.
Assessment Strategies:

Determine if the students understand how the puzzle and compounds are similar by guiding the students in a class discussion or using Socrative.  Use the following open-ended questions on Socrative:

  1. How do puzzle pieces join together? Puzzle pieces join together when the tab of one piece fits into the slot of another.

  2. How do atoms join together? Atoms join together when they share valence electrons.
  3. How are puzzle pieces similar to atoms? They both make connections and create something.
  4. Which parts of the puzzle pieces are similar to the valence electrons in an atom? The tabs of a puzzle are like valence electrons.

Advanced Preparation:

Students should have prior knowledge of the following:

  • Students must have an understanding of valence electrons.
  • Students must have an understanding of chemical bonds.
  • Students must have an understanding of atoms.


Teachers should gather the following materials to complete this learning activity:

  1. Jigsaw Puzzles (I went to Dollar Tree and bought 48 piece puzzles for $1 each.)
  2. Timer
  3. Electronic devices for students to use for Socrative.
Variation Tips (optional):
Notes or Recommendations (optional):

Socrative is an app for fun and effective classroom engagement. Get instant insight into student learning with easy-to-create quizzes, polls, exit tickets and more.

The teacher will create a free Socrative account using:

Students will log into Socrative using:

  Keywords and Search Tags  
Keywords and Search Tags: Atoms, Compounds, Covalent Bond