Copper and calcium both form +2 ions, but copper is far less reactive. Suggest an explanation, taking into account the ground-state electron configurations of these elements and their atomic radii.

Name: Chemistry: The Central Science
Author: Brown
ISBN: 9780134414232

Verified step by step guidance

Step 1: Identify the ground-state electron configurations of copper (Cu) and calcium (Ca). Copper has the electron configuration [Ar] 3d^10 4s^1, while calcium has [Ar] 4s^2.

Step 2: Consider the electron removal process for both elements to form +2 ions. For copper, electrons are removed from the 4s and then the 3d orbitals, while for calcium, electrons are removed from the 4s orbital.

Step 3: Analyze the stability of the electron configurations after ionization. Copper achieves a stable, filled 3d^10 configuration after losing two electrons, which contributes to its lower reactivity.

Step 4: Compare the atomic radii of copper and calcium. Copper has a smaller atomic radius than calcium, which means its valence electrons are held more tightly by the nucleus, reducing its reactivity.

Step 5: Conclude that the filled d-subshell in copper and its smaller atomic radius contribute to its lower reactivity compared to calcium, which has a larger atomic radius and lacks a filled d-subshell.

Key Concepts

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

Electron Configuration

The electron configuration of an element describes the distribution of electrons in its atomic orbitals. For copper (Cu), the ground-state configuration is [Ar] 3d10 4s1, while calcium (Ca) has a configuration of [Ar] 4s2. The presence of a filled d-subshell in copper contributes to its stability and lower reactivity compared to calcium, which has two electrons in its outermost s-subshell that are more easily lost.

Atomic Radius

Atomic radius refers to the size of an atom, typically measured from the nucleus to the outermost electron shell. Copper has a smaller atomic radius than calcium due to its higher nuclear charge, which pulls the electrons closer to the nucleus. A smaller atomic radius can lead to stronger attraction between the nucleus and the valence electrons, making it more difficult for copper to lose electrons and thus reducing its reactivity.

Reactivity of Metals

The reactivity of metals is influenced by their ability to lose electrons and form positive ions. Metals with fewer valence electrons, like calcium, tend to be more reactive because they can easily lose these electrons to achieve a stable electron configuration. In contrast, copper's filled d-subshell and smaller atomic radius make it less inclined to lose its single 4s electron, resulting in lower reactivity compared to calcium.

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