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Date: 25-1-2019
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Date: 20-12-2018
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Date: 10-1-2019
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If the outer valence electrons are not near the nucleus, it does not take as much energy to remove them. Therefore, the energy required to pull off the outermost electron is not as high for the elements at the bottom of the group since there are more energy levels. Also, the high ionization energy makes the element appear non-metallic. Iodine and astatine display metallic properties, so ionization energy decreases down the group (At < I < Br < Cl < F).
Halogen | First Ionization Energy (kJ/mol) |
---|---|
Fluorine | 1681 |
Chlorine | 1251 |
Bromine | 1140 |
Iodine | 1008 |
Astatine | 890±40 |
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دراسة: خطر يتعرض له الملايين يفاقم خطر الإصابة بالباركنسون
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الأمم المتحدة: ذوبان الجليد يهدد إمدادات الغذاء والماء لملياري شخص حول العالم
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مجمّع أبي الفضل العباس (عليه السلام) يقدّم وجبة الإفطار للزائرين في شهر رمضان
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