Matter Interactions Unit Test

Question

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Question
Cobalt has a mass number of 59 and an atomic number of 27. A student wants to create a model of a cobalt atom. Which statement about the model is correct?(1 point)
Responses

The model should show 59 protons and 27 neutrons.
The model should show 59 protons and 27 neutrons.

The model should show 32 protons and 59 neutrons.
The model should show 32 protons and 59 neutrons.

The model should show 27 protons and 32 neutrons.
The model should show 27 protons and 32 neutrons.

The model should show 27 protons and 27 neutrons.

Answer 1

To determine the correct statement about the model of a cobalt atom, we need to understand the definitions of mass number and atomic number:

• The atomic number (27 for cobalt) represents the number of protons in the atom.
• The mass number (59 for cobalt) is the total number of protons and neutrons in the atom.

To find the number of neutrons, we can use the following formula:

\[ \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \]

For cobalt:

• Number of protons = Atomic number = 27
• Mass number = 59

Now, we can calculate the number of neutrons:

\[ \text{Number of neutrons} = 59 - 27 = 32 \]

Now we can analyze the responses:

1. The model should show 59 protons and 27 neutrons. - Incorrect.
2. The model should show 32 protons and 59 neutrons. - Incorrect.
3. The model should show 27 protons and 32 neutrons. - Correct.
4. The model should show 27 protons and 27 neutrons. - Incorrect.

The correct response is: The model should show 27 protons and 32 neutrons.