What is the effective nuclear charge experienced by the valence electrons
in each of the following?
a) Ca
Answer
Zeff = +2
Explanation
If we complete the table below for a calcium atom
Element
|
Nuclear
Charge
|
Electron
Configuration
|
Inner Core
Electrons
|
Valence
Electrons
|
Effective Nuclear
Charge
|
Ca
|
20
|
1s22s22p63s23p64s2
|
18
|
2
|
+2
|
The effective nuclear charge is determined by subtracting from the number
of protons in the nucleus (Z), the number of inner core (I.C.) electrons that
shield the valence electron from the nucleus.
Zeff = Z - I.C.
For calcium
Zeff = 20 - 18 = +2