Element Atomic number Atomic radius (pm) Effective nuclear charge (Zeff)
Sodium 186 90
Magnesium 160 109
Aluminum 143 130
Silicon
111 138
Phosphorous 107 150
Sulfur 100 163
Chlorine 98 180
Argon 94 195
To find the missing values for Silicon in the table, we first need to understand the relationship between atomic radius, effective nuclear charge (Zeff), and atomic number.
Atomic radius generally decreases as you move across a period from left to right because the effective nuclear charge increases, pulling the electrons closer to the nucleus. This explains why the atomic radius decreases from Sodium to Argon in the table.
Effective nuclear charge (Zeff) also increases across a period from left to right. Zeff is a measure of the attractive force experienced by the outermost electrons in an atom. It increases as the number of protons in the nucleus increases, attracting the electrons more strongly.
Since Silicon has an atomic number of 14, it falls between Aluminum (13) and Phosphorous (15) in the table. We can estimate the missing values for Silicon by considering this trend.
Estimated values for Silicon:
Atomic radius: between 143 pm (Aluminum) and 107 pm (Phosphorous), so around 125 pm
Effective nuclear charge (Zeff): between 130 (Aluminum) and 150 (Phosphorous), so around 140
So, for Silicon:
Atomic number: 14
Atomic radius: 125 pm
Effective nuclear charge (Zeff): 140