Question

The elements \(\mathrm{Si}\), Ga, As, Ge, Al, \(\mathrm{Cd}, \mathrm{S}\), and Se are all used in the manufacture of various semiconductor devices. Write the expected electron configuration for these atoms.

Short answer

The electron configurations of the given elements are: - Si: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{2}\] - Ga: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{1}\] - As: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{3}\] - Ge: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{2}\] - Al: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{1}\] - Cd: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{6} 5s^{2} 4d^{10}\] - S: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{4}\] - Se: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{4}\]

Step-by-step solution

1. Periodic Table Reference

Always have a periodic table as a reference. This will help us determine each element's atomic number, which gives the number of protons and electrons in a neutral atom.

2. Write down the atomic numbers

Using the periodic table, write down the atomic numbers for each element: Si (14), Ga (31), As (33), Ge (32), Al (13), Cd (48), S (16), and Se (34)

3. Electron configuration general order

Remember the electron configuration general order based on the Aufbau principle: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, and so on. Follow this order to fill in electrons.

4. Fill in the electrons

Fill in the electrons, always remembering that s orbitals can hold 2 electrons, p orbitals can hold 6, d orbitals can hold 10, and f orbitals can hold 14. For example, let's take Silicon (Si, Atomic number: 14) 1. Start with the lowest energy level orbital (1s): 1s^2 (2 electrons) 2. Move to the next orbital (2s): 2s^2 (2 electrons) 3. Keep filling: 2p^6 (6 electrons) 4. Next orbital is 3s: 3s^2 (2 electrons) 5. Finally, begin filling the 3p orbital: 3p^2 (2 electrons) Adding all these configurations together, we get the electron configuration for Si: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{2}\] Repeat this process for the other elements: - Ga: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{1}\] - As: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{3}\] - Ge: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{2}\] - Al: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{1}\] - Cd: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{6} 5s^{2} 4d^{10}\] - S: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{4}\] - Se: \[1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{10} 4p^{4}\] These are the expected electron configurations of the given elements.

Key concepts

Aufbau Principle

When it comes to understanding how electrons occupy an atom's orbitals, the Aufbau principle is a fundamental guide. It's a German term that translates to 'building up' and it refers to the sequence in which electrons fill the subatomic orbitals of an atom.

The principle suggests that electrons will first occupy the lowest energy orbitals available. In simple terms, electrons are like people trying to find seats in a theater - they will fill the front row before moving to the back. This analogy helps visualize why the 1s orbital is filled before the 2s orbital, and so on.

To apply the Aufbau principle effectively, one must be familiar with the types of orbitals (s, p, d, f) and their order based on increasing energy. Remembering this order is crucial:

• 1s
• 2s
• 2p
• 3s
• 3p
• 4s
• 3d
• 4p
• 5s
• 4d
• 5p
• 6s
• 4f
• 5d
• 6p
• 7s

Keep in mind that each orbital can only hold a maximum number of electrons (s: 2, p: 6, d: 10, and f: 14), and you'll need to fill lower-energy orbitals before moving to higher ones.

Periodic Table

The periodic table is like a map for chemists and physicists alike, charting all known elements in an organized manner. Each element's placement on the table is not random; it actually provides a wealth of information about the properties of that element, including its electron configuration.

Elements are arranged in order of increasing atomic number, which also equates to the number of protons and, in a neutral atom, the number of electrons. Every row and column tells a story: rows, or periods, indicate the number of electron shells, while columns, or groups, reflect elements with similar valence electron configurations. This layout gives clues about how atoms will interact or bond with each other.

Using the periodic table is essential when deciphering electron configuration. It helps us to systematically build the electronic structure, as exemplified by the elements used in semiconductor devices. By referring to their atomic numbers, we can determine how many electrons need to be placed according to the Aufbau principle.

Semiconductor Devices

Semiconductor devices form the backbone of modern electronics, ranging from our smartphones to solar cells. Elements used in these devices, like silicon and gallium, are chosen carefully due to their ability to conduct electricity under certain conditions—better than insulators but not as well as conductors.

Their unique conducting properties are due to their electron configurations, with a small number of electrons available for conduction. For instance, silicon has a configuration that allows it to form crystal lattices with a perfect balance – it's not too eager to lose electrons, nor is it too reluctant. Through a process called doping, where impurities (other elements) are added, the semiconductor's properties can be manipulated to enhance conductivity or create junctions necessary for the operation of transistors and diodes.

Understanding the electron configurations of elements like Si, Ga, and others is crucial because it affects how they can be used in semiconductor devices. It informs us about the behavior of valence electrons, which are the primary actors in semiconductor conductivity and functionality.