Question

Use the Aufbau principle to obtain the ground-state electron configuration of technetium.

Short answer

Technetium's electron configuration is \( 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^5 \).

Step-by-step solution

Identify Technetium's Atomic Number

Technetium (Tc) has an atomic number of 43, which means it has 43 electrons in its neutral state. Knowing the atomic number is essential to determine the electron configuration.

Understand the Aufbau Principle

The Aufbau principle states that electrons occupy orbitals starting from the lowest energy level to the highest. The order of filling is typically: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, and so on.

Follow the Electron Filling Order

Let’s place the 43 electrons in orbitals following the Aufbau principle: 1. Fill the 1s orbital: 2 electrons 2. Fill the 2s orbital: 2 electrons 3. Fill the 2p orbital: 6 electrons 4. Fill the 3s orbital: 2 electrons 5. Fill the 3p orbital: 6 electrons 6. Fill the 4s orbital: 2 electrons 7. Fill the 3d orbital: 10 electrons 8. Fill the 4p orbital: 6 electrons 9. Fill the 5s orbital: 2 electrons 10. Fill the 4d orbital with the remaining electrons, which is 5.

Write the Electron Configuration

According to Step 3, the electron configuration for technetium is: \[ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^5 \] This configuration accounts for all 43 electrons.

Key concepts

Electron Configuration

Electron configuration is a systematic way of describing the arrangement of electrons in an atom's electron orbitals. It plays a key role in understanding an element's chemical properties and behavior.
To determine an element's electron configuration, we need to follow specific rules such as the Aufbau principle, which guides the order in which electrons are filled in different energy levels and orbitals.

• Start filling from the lowest energy level and gradually move to higher ones.
• Each orbital can hold a specific number of electrons: 2 in s orbitals, 6 in p orbitals, 10 in d orbitals, etc.
• The notation like \( 1s^2 \) indicates the orbital name and the number of electrons in that orbital.

Understanding electron configurations allows chemists to predict and explain the chemical behavior of elements.

Atomic Number

The atomic number is a fundamental property of an element, represented by the symbol \( Z \). It tells us the number of protons in an atom, which is also equal to the number of electrons in a neutral atom.
For example, Technetium has an atomic number of 43, indicating it has 43 protons and 43 electrons.

• This number is unique for each element and determines the element's identity.
• It also influences the position of the element in the periodic table, guiding us in predicting its chemical properties.
• Knowing the atomic number is crucial for writing correct electron configurations.

Thus, for Technetium, knowing it has 43 electrons helps us allocate these electrons into the respective orbitals using the Aufbau principle.

Electron Orbitals

Electron orbitals are regions around an atom's nucleus where electrons are likely to be found. These orbitals have different shapes and energy levels, which affect how electrons fill them.
Key concepts about electron orbitals include:

• **s, p, d, and f orbitals**: These types of orbitals have different shapes and capacities. * **s orbitals**: Spherical and can hold up to 2 electrons. * **p orbitals**: Dumbbell-shaped and can hold up to 6 electrons. * **d orbitals**: More complex shapes, holding up to 10 electrons. * **f orbitals**: Even more complex, can hold up to 14 electrons.
• The order in which these orbitals are filled affects the chemical properties of the element.
• Higher energy orbitals are filled only after the lower energy orbitals are completely filled, following Hund's Rule and the Pauli exclusion principle.

Understanding orbitals is crucial for writing accurate electron configurations and predicting chemical behavior.

Technetium

Technetium (symbol: Tc) is a chemical element with the atomic number 43. It was the first artificially produced element and is a part of the d-block in the periodic table.
Some essential facts about Technetium are:

• It has no stable isotopes and is naturally found in minute quantities in the Earth's crust.
• It plays a significant role in nuclear medicine, particularly in diagnostic imaging.
• Technetium's electron configuration, as determined by the Aufbau principle, is \( 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^5 \).

Understanding Technetium's electron configuration helps in the study of its chemical and physical properties, which can be leveraged in various scientific and industrial applications.