A teacher has students use dkerent materials to model the structure of an atom. Baseballs represent protons, marbles represent electrons and tennis balls represent neutrons. Sodium um atom with an atomic mass of 23? Using the information in the image above, what materials will the students need to build a typical s sodium A. 5 baseballs, 5 marbles,1 tennis ball B. 11 baseballs, 11 marbles, 12 tennis balls

## Step 1<br />The atomic number of an element represents the number of protons in its nucleus. For sodium, the atomic number is 11, which means it has 11 protons. In the model, protons are represented by baseballs. Therefore, the sodium atom will need 11 baseballs to represent its protons.<br /><br />## Step 2<br />The atomic mass of an element is the sum of the number of protons and neutrons in its nucleus. Sodium has an atomic mass of 23. Since it has 11 protons (from the atomic number), it must have 12 neutrons to make the total atomic mass 23. In the model, neutrons are represented by tennis balls. Therefore, the sodium atom will need 12 tennis balls to represent its neutrons.<br /><br />## Step 3<br />Electrons are represented by marbles in the model. The number of electrons in a neutral atom is equal to the number of protons. Since sodium has 11 protons, it will also have 11 electrons. Therefore, the sodium atom will need 11 marbles to represent its electrons.<br /><br />## Step 4<br />Combining the information from the above steps, the sodium atom will need 11 baseballs, 11 marbles, and 12 tennis balls to represent its structure.