Model Student

Despite the quality of the product, it should be known that Emmie built this quicker than she ate it (and it was consumed within seconds of Mom taking a picture). 

KEY:

Red - Calcium (Ca)

Orange - Oxygen (O)

Yellow - Carbon (C)

The gumdrop model represents the formula:

CaCO₃ —> CaO + CO₂

The left side of the model represents the reactants. Calcium Carbonate (CaCO₃) is the reactant in this case. When Calcium Carbonate, the reactant, is heated, Carbon Dioxide (CO₂) is released and Calcium Oxide (CaO) is formed. The Carbon Dioxide and Calcium Oxide are the products and displayed on the right side of the chemical formula.

The law of conservation of mass “is the natural law that states the same amount of mass is present before and after a chemical reaction. In other words, the total number of atoms of each element before and after a chemical reaction remains the same.” This is displayed in the model by the fact that there are 3 Oxygen atoms, 1 Calcium atom and 1 Carbon atom on each side of the arrow. There are 3 orange, 1 red and 1 yellow on both the left and the right.

The periodic table can be used to figure out how the atoms bond. The octet rule “is a chemical rule that reflects the observation that main group elements tend to bond in such a way that each atom has eight electrons in its valence shell.” The periodic table shows that Calcium has 2 electrons in its valence shell, Carbon has 4 and Oxygen has 6. This explains how the bonds/toothpicks connect in the model:

CaCO₃: Carbon gives 2 electrons to one of the Oxygen atoms. Carbon gives 1 electron to the other 2 Oxygen atoms. These two Oxygen atoms now have 7 so Calcium gives them each 1. 

CaO: Calcium gives 2 electrons to Oxygen.

CO₂: Carbon gives 2 electrons to each Oxygen.