If core electrons completely shielded valence electrons from nuclear charge (i.e., if each core electron reduced nuclear charge by 1 unit) and if valence electrons did not shield one another from nuclear charge at all, what would be the effective nuclear charge experienced by the valence electrons of each atom? b. Ca

Verified step by step guidance

1. Identify the atomic number of calcium (Ca), which is 20.
2. Determine the number of core electrons in calcium. Calcium has an electron configuration of [Ar] 4s^2, so it has 18 core electrons (the electrons in the argon core).
3. Apply the concept of effective nuclear charge (Z_eff), which is calculated as Z_eff = Z - S, where Z is the atomic number and S is the number of core electrons.
4. Substitute the values into the formula: Z_eff = 20 (atomic number of Ca) - 18 (number of core electrons).
5. Conclude that the effective nuclear charge experienced by the valence electrons of calcium is the result of the calculation from the previous step.

Key Concepts

Effective Nuclear Charge (Z_eff)

Effective nuclear charge (Z_eff) is the net positive charge experienced by valence electrons in an atom. It accounts for the actual nuclear charge (the number of protons) minus the shielding effect of core electrons. In this scenario, if each core electron reduces the nuclear charge by 1 unit, Z_eff can be calculated by subtracting the number of core electrons from the total nuclear charge.

Shielding Effect

The shielding effect refers to the phenomenon where inner (core) electrons repel valence electrons, reducing the full attractive force of the nucleus on these outer electrons. In this question, it is assumed that core electrons completely shield valence electrons, meaning that each core electron effectively cancels out one unit of nuclear charge, simplifying the calculation of Z_eff.

Valence Electrons

Valence electrons are the outermost electrons of an atom and are primarily responsible for chemical bonding and reactivity. In the context of this question, understanding the number of valence electrons in calcium (Ca) is crucial, as it determines how they interact with the effective nuclear charge and influences the atom's chemical properties.