1. What is Effective Nuclear Charge?

Effective Nuclear Charge (ENC) is the net positive charge experienced by an electron in an atom. It accounts for both the attraction from the nucleus and the repulsion from other electrons.

2. How Does the Calculator Work?

The calculator uses the simple ENC equation:

Where:

• \( Z \) — Atomic number (number of protons)
• \( S \) — Shielding constant (measure of electron shielding)

Explanation: The equation shows that the effective nuclear charge is the atomic number minus the shielding effect of other electrons.

3. Importance of ENC Calculation

Details: ENC helps predict atomic properties like atomic radius, ionization energy, and electronegativity. It's fundamental in understanding periodic trends.

4. Using the Calculator

Tips: Enter the atomic number (1-118) and shielding constant (≥0). The shielding constant can be estimated using Slater's rules or other methods.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of ENC values?
A: ENC typically ranges from about +1 to the atomic number (Z), though exact values depend on electron configuration.

Q2: How does ENC vary across the periodic table?
A: ENC generally increases across a period and decreases down a group, explaining many periodic trends.

Q3: What's the difference between Z and ENC?
A: Z is the actual nuclear charge, while ENC is the net charge experienced by an electron after accounting for shielding.

Q4: How accurate is this simple calculation?
A: This gives a basic estimate. More accurate calculations consider specific electron configurations and quantum mechanical effects.

Q5: Can ENC be negative?
A: No, ENC is always positive since the nuclear charge always exceeds the shielding effect in neutral atoms.