Allred-Rochow's Electronegativity Formula:
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Definition: Allred-Rochow's electronegativity is a measure of the power of an atom in a molecule to attract electrons to itself.
Purpose: It helps predict the nature of chemical bonds and reactivity of elements in compounds.
The calculator uses the formula:
Where:
Explanation: The formula relates electronegativity to the effective nuclear charge experienced by valence electrons and the covalent radius of the atom.
Details: Electronegativity values help predict bond polarity, molecular dipole moments, and chemical reactivity trends in the periodic table.
Tips: Enter the effective nuclear charge and covalent radius (in Ångströms). All values must be > 0.
Q1: What is effective nuclear charge?
A: The net positive charge experienced by an electron in an atom, accounting for shielding by inner electrons.
Q2: How is covalent radius measured?
A: It's half the distance between two identical atoms bonded by a single covalent bond.
Q3: What's the range of Allred-Rochow electronegativity values?
A: Typically ranges from about 0.7 for cesium to 3.5 for fluorine.
Q4: How does this scale compare to Pauling's scale?
A: Both scales show similar trends, but numerical values differ. Pauling's scale is more commonly used.
Q5: Why is the constant 0.359 used?
A: This empirical constant scales the relationship to match observed electronegativity trends.