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Ch.2 - Atoms, Molecules & Ions
Chapter 2, Problem 116

Copper has two naturally occurring isotopes, including 65Cu. Look at the periodic table and tell whether the second isotope is 63Cu or 66Cu.

Verified step by step guidance
1
Step 1: Understand that the atomic mass of an element on the periodic table is a weighted average of the masses of its naturally occurring isotopes.
Step 2: Locate copper (Cu) on the periodic table and note its atomic mass, which is approximately 63.55 amu.
Step 3: Recognize that copper has two naturally occurring isotopes: 65Cu and another isotope that we need to identify.
Step 4: Consider the possible isotopes: 63Cu and 66Cu. The atomic mass of copper (63.55 amu) is closer to 63 than to 66.
Step 5: Conclude that the second isotope is likely 63Cu, as the average atomic mass (63.55 amu) is closer to 63 than to 66, indicating a higher abundance of 63Cu compared to 65Cu.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Isotopes

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons. This results in different atomic masses for the isotopes. For example, copper has isotopes like 63Cu and 65Cu, where the numbers represent the total number of protons and neutrons in the nucleus.
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Atomic Mass

Atomic mass is the weighted average mass of an element's isotopes, measured in atomic mass units (amu). It reflects the relative abundance of each isotope in nature. In the case of copper, the atomic mass listed on the periodic table is influenced by the presence of its isotopes, which helps in identifying them.
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Periodic Table

The periodic table organizes elements based on their atomic number, electron configuration, and recurring chemical properties. Each element's position provides information about its isotopes, atomic mass, and other characteristics. By examining the periodic table, one can determine the most common isotopes of an element, such as copper's isotopes 63Cu and 65Cu.
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Periodic Table Classifications