Draw orbital-filling diagrams for the following atoms. Show each electron as an up or down arrow, and use the abbreviation of the preceding noble gas to represent inner-shell electrons. (a) Sr (b) Cd (c) Atom with Z = 22 (d) Atom with Z = 34

Verified step by step guidance

Step 1: Identify the electron configuration for each atom using the periodic table. For Sr (Strontium), Cd (Cadmium), and the atoms with atomic numbers Z = 22 and Z = 34, determine the number of electrons and their distribution in orbitals.

Step 2: Use the noble gas abbreviation to represent inner-shell electrons. For example, for Sr, use [Kr] to represent the inner-shell electrons, and then add the remaining electrons in the appropriate orbitals.

Step 3: Draw the orbital-filling diagram for each atom. Start with the lowest energy level and fill the orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle. Use up and down arrows to represent electrons with opposite spins.

Step 4: For Sr, after [Kr], fill the 5s orbital with two electrons. For Cd, after [Kr], fill the 4d orbital with ten electrons and the 5s orbital with two electrons.

Step 5: For the atom with Z = 22 (Titanium), use [Ar] and fill the 3d orbital with two electrons and the 4s orbital with two electrons. For the atom with Z = 34 (Selenium), use [Ar] and fill the 3d orbital with ten electrons, the 4s orbital with two electrons, and the 4p orbital with four electrons.

Key Concepts

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

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. It follows the Aufbau principle, which states that electrons fill the lowest energy orbitals first, and is often represented using the notation of noble gas core followed by the valence electrons. Understanding electron configuration is essential for predicting chemical behavior and bonding.

Orbital Diagrams

Orbital diagrams visually represent the arrangement of electrons in an atom's orbitals. Each orbital can hold a maximum of two electrons, which are depicted as arrows pointing up (↑) and down (↓) to indicate their spin. These diagrams help illustrate the Pauli exclusion principle and Hund's rule, which govern electron placement in orbitals.

Noble Gas Core

The noble gas core refers to the electron configuration of the nearest noble gas that precedes a given element in the periodic table. This shorthand notation simplifies the representation of electron configurations by indicating the filled inner-shell electrons, allowing chemists to focus on the valence electrons that are crucial for chemical reactivity and bonding.

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Imagine a universe in which the four quantum numbers can have the same possible values as in our universe except that the angular-momentum quantum number l can have integral values of 0, 1, 2...n + 1 (instead of 0, 1, 2..., n - 1). (c) Draw an orbital-filling diagram for the element with atomic number 12.

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