Activity

An atom consists of electrons, protons, and neutrons. Each electron has a charge of -1, each proton has a charge of +1, and each neutron has no charge. If 3 electrons are removed from each of 4 atoms, what is the combined net change to the charge of the 4 atoms?

Complete the steps below to solve this problem and others like it.

Part A
Three electrons are removed from each of 4 atoms. Write an expression to represent the net change on the charge for the group of atoms.

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Part B
Simplify the expression obtained in part A and explain what the answer represents.

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Part C
Here’s a similar problem. Write an expression for the net change in charge if two electrons are added to each of six atoms in a group. Also, write an expression that represents removing two protons each from a group of six atoms.

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Part D
Simplify the two expressions in part C.

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Part E
How are the two products in part D related?

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Part F
Think about multiplying any two rational numbers. Based on this activity and your previous work, write a set of rules for finding the sign of the product based on the sign of the two numbers being multiplied.

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Self-Evaluation
How did you do? Rate your work on a scale of 1 to 5, with 5 as the highest score. Then write a brief evaluation of your work below. Note what you learned and what challenged you.

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can you give me the answers

1 answer

Sure! Let's go through the activity step by step and provide the answers for each part.

Part A

When 3 electrons are removed from each of 4 atoms, the charge change can be expressed as: \( \text{Net Change} = 4 \times (-3) \) This is because removing an electron (which has a charge of -1) is equivalent to adding +1 charge, so removing 3 electrons from one atom changes its charge by +3.

Part B

Now let's simplify the expression: \[ \text{Net Change} = 4 \times (-3) = -12 \] This means that the total net change in charge for the 4 atoms is -12. The negative sign indicates that the overall charge has decreased by 12 units due to the removal of electrons.

Part C

  1. For adding two electrons to each of six atoms: \[ \text{Net Change (adding)} = 6 \times (+2) \]

  2. For removing two protons each from six atoms (noting that each proton has a charge of +1): \[ \text{Net Change (removing)} = 6 \times (-2) \]

Part D

Let's simplify both expressions:

  1. For adding two electrons: \[ \text{Net Change (adding)} = 6 \times (+2) = +12 \]
  2. For removing two protons: \[ \text{Net Change (removing)} = 6 \times (-2) = -12 \]

Part E

The two products in Part D are related by their magnitudes being the same but differing in sign:

  • Adding two electrons results in a positive change (+12).
  • Removing two protons results in a negative change (-12). This shows that both actions have equivalent magnitudes of charge change but opposite effects on the overall charge of the group of atoms.

Part F

Based on the activity and previous work, here is a set of rules for finding the sign of the product of two rational numbers:

  1. Positive × Positive = Positive: Multiplying two positive numbers results in a positive product.
  2. Negative × Negative = Positive: Multiplying two negative numbers results in a positive product (the negatives cancel out).
  3. Positive × Negative = Negative: Multiplying a positive number by a negative number results in a negative product.
  4. Negative × Positive = Negative: Multiplying a negative number by a positive number also results in a negative product.

Self-Evaluation

You can rate your work based on clarity, correctness, and completeness; here's one possible evaluation:

  • Rating: 5
  • Evaluation: I provided clear explanations and completed all parts of the activity correctly. I learned how to represent changes in atomic charges through mathematical expressions and how actions can have different effects based on whether charge is added or removed.

If you have any additional questions or need further assistance, feel free to ask!