اختبار مقنن في الفصل الثاني

The elements in the same group of the periodic table have the same number of valence electrons. Valence electrons are the electrons in the outermost energy level of an atom and they determine the chemical reactivity and bonding behavior of an element. Therefore, elements in the same group have similar chemical properties because they have the same number of valence electrons available for bonding.

أشباه الفلزات توجد فقط في المجموعات 13 إلى 17 في الجدول الدوري. هذه المجموعات تسمى أيضًا بالمجموعات العقيدة وتشمل العناصر مثل البورون والسيليكون والجرمانيوم والزرنيخ والأنتيمون والتيلوريوم. تتميز أشباه الفلزات بأنها تمتلك خصائص مشابهة للفلزات واللافلزات، حيث يمكن أن توصف بأنها موصلات ضعيفة للكهرباء والحرارة ولكنها تظهر أيضًا بعض الخصائص اللافلزية مثل الشفافية والهشاشة.

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The element Z falls under the p category.

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The correct answer is "مجموعة 16، دورة 4، فئة p". This is because in the periodic table, the group number represents the number of valence electrons an atom of that element has. Group 16 elements have 6 valence electrons. The period number represents the energy level or shell in which the valence electrons are found. Period 4 means that the valence electrons are in the fourth energy level. Finally, the letter "p" represents the type of subshell in which the valence electrons are located. So, the correct answer indicates that the atom in question belongs to Group 16, is in Period 4, and has valence electrons in the p subshell.

The statement is incorrect because the atomic radius of sodium (Na) is larger than the atomic radius of magnesium (Mg).

The correct answer is 36.8%. This means that the compound contains 36.8% of nitrogen.

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The correct answer is 13,15. These two numbers belong to the group of semi-metals or metalloids. Semi-metals are elements that have properties of both metals and non-metals. They have characteristics such as being good conductors of electricity and heat, but also have low melting and boiling points. Therefore, the group that contains semi-metals is 13,15.