Amos is using three different colors of candy to create atomic models. He constructs a model of an oxygen atom as demonstrated. There are a bunch of red and green candies in the middle mixed together, and there are a bunch of blue candies spread out further from the circle or red and green. Amos wants to modify this model to represent a different isotope of oxygen. What adjustments could he make to achieve this? A red candy is a proton, a green candy is a neutron, and a blue candy is a electron. There are a total of 8 red candies and 10 green ones. There are a total of 10 blue candies.

Answer 1

To depict a different isotope of oxygen, Amos needs to consider how isotopes differ from one another. Isotopes of an element have the same number of protons (which determines the element) but differ in the number of neutrons.

In the oxygen model Amos has constructed, there are:

• 8 red candies (protons)
• 10 green candies (neutrons)
• 10 blue candies (electrons)

Given that oxygen has 8 protons (the atomic number), this model represents the isotope oxygen-18 (which has 8 protons and 10 neutrons).

To represent a different isotope, he should adjust the number of green candies (neutrons) while keeping the number of red candies (protons) constant at 8.

For example:

1. If he wants to represent oxygen-16, which has 8 protons and 8 neutrons, he should reduce the green candies from 10 to 8.
2. If he wants to represent oxygen-17, which has 8 protons and 9 neutrons, he should remove one green candy to have 9 green candies.

The number of blue candies (electrons) remains at 10 since the number of electrons is equal to the number of protons in a neutral atom, and since the number of protons does not change, the electrons should remain the same.

To summarize, to modify the model to create a different isotope of oxygen, Amos can:

• Remove or add green candies (neutrons) according to the desired isotope while keeping the red candies (protons) at 8.
• Keep the blue candies (electrons) at 10 for a neutral atom.