Problem 103 - Chemistry Matter and Change

Question

Semiconductors Silicon is important to the semiconductor manufacturing industry. The three naturally occuring isotopes of silicon are silicon-28, silicon-29, and silicon-30. Write the symbol for each.

Step-by-Step Solution

Answer

The symbols for the three naturally occurring isotopes of Silicon are: Silicon-28: \(_{14}^{28}\textrm{Si}\), Silicon-29: \(_{14}^{29}\textrm{Si}\), and Silicon-30: \(_{14}^{30}\textrm{Si}\).

Step 1: Silicon-28

The symbol for Silicon-28 is \(_{14}^{28}\textrm{Si}\), where 14 is the atomic number and 28 is the mass number.

Step 2: Silicon-29

The symbol for Silicon-29 is \(_{14}^{29}\textrm{Si}\), where 14 is the atomic number and 29 is the mass number.

Step 3: Silicon-30

The symbol for Silicon-30 is \(_{14}^{30}\textrm{Si}\), where 14 is the atomic number and 30 is the mass number.

Key Concepts

Understanding Isotope Symbols

Isotope symbols provide crucial information about specific atoms and their properties. These symbols typically consist of the atomic number, chemical symbol, and mass number. Let's break down what each part represents:

• Atomic Number: This number is unique to each element and corresponds to the number of protons in the nucleus. For silicon, the atomic number is 14, which stays the same for all its isotopes.
• Mass Number: Found at the upper corner of the isotope symbol, it indicates the total number of protons and neutrons in the nucleus.
• Chemical Symbol: This is the letter designation for the element, such as Si for silicon.

These parts form a concise symbol like \(_{14}^{28}\textrm{Si}\) for silicon-28, where 14 is the atomic number and 28 is the mass number. Understanding these components helps in identifying and distinguishing between different isotopes of an element.

Introducing Silicon Isotopes

Silicon is a fundamental element in semiconductor technology and naturally occurs in three isotopic forms: silicon-28, silicon-29, and silicon-30. These isotopes have the same number of protons but differ in the number of neutrons in their nuclei.

Silicon-28, represented by the symbol \(_{14}^{28}\textrm{Si}\), is the most abundant, comprising about 92.23% of natural silicon. It has 14 protons and 14 neutrons.

On the other hand, silicon-29 \(_{14}^{29}\textrm{Si}\) has one additional neutron, totaling 15 neutrons. It accounts for approximately 4.67% of silicon found in nature. Silicon-30 \(_{14}^{30}\textrm{Si}\), with 16 neutrons, makes up approximately 3.1% of silicon.

These differences in neutron number can influence physical properties, making understanding these isotopes significant for fields like materials science and semiconductor manufacturing.

The Significance of Mass Number

The mass number of an isotope tells us the total count of protons and neutrons present in an atom's nucleus. While the atomic number determines the element, the mass number provides insight into the particular isotope. This distinction is significant due to its impact on the atom's properties.

Mass number varies between isotopes of the same element because the number of neutrons changes. For silicon, the isotopes are defined by their mass numbers 28, 29, and 30. Each of these numbers tells us how the total mass in atomic mass units might differ between isotopes.

• The mass number is critical for calculating the atomic mass of the element as found in nature, which considers the relative abundance of each isotope.
• It's also essential for predicting nuclear stability and behavior, particularly important in scientific applications such as silicon-based electronics.

Understanding the mass number enhances our ability to work with isotopes in practical, everyday applications.