Question

1. use a periodic table to fill in all the blank spaces in the chart.
2. silicon has 3 stable isotopes: si - 28 (92.23%), si - 29 (4.67%), and si - 30 (3.1%).

calculate the average atomic mass of silicon.

Explanation:

Step1: <Formula for average atomic mass>

The formula for average atomic mass \(M\) is \(M=\sum_{i = 1}^{n}m_i\times p_i\), where \(m_i\) is the mass of the \(i -\)th isotope and \(p_i\) is the percentage abundance (in decimal form) of the \(i -\)th isotope.
For silicon, \(n = 3\), \(m_1=28\), \(p_1 = 0.9223\), \(m_2 = 29\), \(p_2=0.0467\), \(m_3 = 30\), \(p_3=0.031\).

Step2: <Calculate each term>

• Term1: \(m_1\times p_1=28\times0.9223 = 25.8244\)
• Term2: \(m_2\times p_2=29\times0.0467=1.3543\)
• Term3: \(m_3\times p_3=30\times0.031 = 0.93\)

Step3: <Sum up the terms>

\(M=25.8244 + 1.3543+0.93\)
\(M=28.1087\approx28.11\)

Answer:

The average atomic mass of silicon is approximately \(28.11\)