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Date: 26-12-2018
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Date: 25-1-2019
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Date: 13-11-2018
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Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values decrease toward cesium and francium which are the least electronegative at 0.7.
The trend across Period 3 looks like this:
Argon is not included; because it does not form covalent bonds, its electronegativity cannot be assigned.
The explanation is the same as that for the trend in atomic radii. Across the period, the valence electrons for each atom are in the 3-level. They are screened by the same inner electrons. The only difference is the number of protons in the nucleus. From sodium to chlorine, the number of protons steadily increases and so attracts the bonding pair more closely.
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علامات بسيطة في جسدك قد تنذر بمرض "قاتل"
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أول صور ثلاثية الأبعاد للغدة الزعترية البشرية
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قدم خدماتها لأكثر من (700) مستفيدة خلال شهر واحد.. مركز تابع لهيئة الصحة والتعليم الطبي في العتبة الحسينية يختتم المبادرة المجانية للكشف المبكر عن سرطان الثدي
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