For the element Cadmium (Cd)

For the element Cadmium (Cd).

Write out the complete electron configuration.

Draw the orbital diagram (boxes with arrows) for its valence (not core) electrons.

The Correct Answer and Explanation is :

iturn0image0Cadmium (Cd) has an atomic number of 48, indicating it possesses 48 electrons in a neutral state. The complete electron configuration for cadmium is:

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s²

This notation details the distribution of electrons across the various atomic orbitals, starting from the lowest energy level (1s) to the highest (5s).

In this configuration, the electrons fill the orbitals in accordance with the Aufbau principle, which states that electrons occupy the lowest energy orbitals first. The sequence follows the order of increasing energy levels:

1. 1s²: 2 electrons in the 1s orbital
2. 2s² 2p⁶: 2 electrons in the 2s orbital and 6 in the 2p orbitals
3. 3s² 3p⁶ 3d¹⁰: 2 electrons in the 3s orbital, 6 in the 3p orbitals, and 10 in the 3d orbitals
4. 4s² 4p⁶ 4d¹⁰: 2 electrons in the 4s orbital, 6 in the 4p orbitals, and 10 in the 4d orbitals
5. 5s²: 2 electrons in the 5s orbital

The valence electrons of an element are those located in the outermost shell, which participate in chemical bonding. For cadmium, the valence electrons are in the 5s orbital. The orbital diagram for these valence electrons can be represented as follows:

5s: ↑↓

In this diagram, the box represents the 5s orbital, and the arrows indicate the electrons with their respective spins. The upward arrow (↑) denotes an electron with one spin orientation, and the downward arrow (↓) denotes an electron with the opposite spin, adhering to the Pauli exclusion principle, which states that no two electrons in an atom can have the same set of quantum numbers.

Understanding the electron configuration and orbital diagram of cadmium is crucial for predicting its chemical behavior. The filled 5s orbital suggests that cadmium commonly exhibits a +2 oxidation state, as it tends to lose the two 5s electrons during chemical reactions to achieve a more stable electron configuration. This characteristic is consistent with cadmium’s placement in group 12 of the periodic table, where elements typically display a +2 oxidation state.

Moreover, the completely filled 4d¹⁰ subshell contributes to the stability of the Cd²⁺ ion, as a filled d-subshell offers a lower energy state. This electron arrangement influences cadmium’s properties, such as its relatively low melting point compared to other transition metals and its tendency to form colorless compounds, since the d-d electron transitions that often impart color are absent in a fully filled d-subshell.

In summary, the electron configuration and valence orbital diagram of cadmium provide insight into its chemical properties and reactivity, highlighting the significance of electron arrangements in understanding elemental behavior.