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Date: 17-2-2016
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Date: 19-2-2019
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Date: 24-4-2019
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Transition metals tend to have particularly high melting points and boiling points. The reason is that they can involve the 3d electrons in the delocalization as well as the 4s. The more electrons you can involve, the stronger the attractions tend to be.
The strength of a metallic bond depends on three things:
A strong metallic bond will be the result of more delocalized electrons, which causes the effective nuclear charge on electrons on the cation to increase, in effect making the size of the cation smaller. Metallic bonds are strong and require a great deal of energy to break, and therefore metals have high melting and boiling points.
A metallic bonding theory must explain how so much bonding can occur with such few electrons (since metals are located on the left side of the periodic table and do not have many electrons in their valence shells). The theory must also account for all of a metal's unique chemical and physical properties.
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زراعة الأسنان.. بين بريق التجميل وحاجة المريض إليها
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وفاة أول رجل خضع لزراعة كلية خنزير.. والمستشفى يوضح الأسباب
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اختتام الأسبوع الثاني من الشهر الثالث للبرنامج المركزي لمنتسبي العتبة العباسية
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راية قبة مرقد أبي الفضل العباس (عليه السلام) تتوسط جناح العتبة العباسية في معرض طهران
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جامعة العميد وقسم الشؤون الفكرية يعقدان شراكة علمية حول مجلة (تسليم)
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قسم الشؤون الفكريّة يفتتح باب التسجيل في دورات المواهب
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