Effective Nuclear Charge Formula:
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Definition: The Effective Nuclear Charge is the net positive charge experienced by an electron in a polyelectronic atom.
Purpose: It helps understand how strongly an electron is attracted to the nucleus, accounting for shielding by other electrons.
The calculator uses the formula:
Where:
Explanation: The shielding constant represents how much the nuclear charge is reduced by intervening electrons.
Details: Effective nuclear charge explains periodic trends like atomic size, ionization energy, and electronegativity.
Tips: Enter the atomic number (must be ≥ 1) and shielding constant (must be ≥ 0). The shielding constant is typically between 0 and Z-1.
Q1: What is the shielding constant?
A: The shielding constant (σ) measures how much an electron is shielded from the nucleus by other electrons.
Q2: How do I determine the shielding constant?
A: It can be calculated using Slater's rules or obtained from experimental data like NMR spectroscopy.
Q3: What's the range for effective nuclear charge?
A: Zeff ranges from just above 0 (for outer electrons) up to Z (for the 1s electron in hydrogen).
Q4: Why does effective nuclear charge increase across a period?
A: While Z increases, shielding increases more slowly, so Zeff increases left to right.
Q5: How does effective nuclear charge affect atomic radius?
A: Higher Zeff pulls electrons closer, decreasing atomic radius.