Periodic table of Elements | Prep.1 | Unit 1 - Lesson 2 - Part (2/2) | Science

شرح ساينس الصف الأول الاعدادي لغات - الفصل الدراسي الأول شرح ساينس سادسة ابتدائي - ترم أول لينك تحميل الملزمة https://drive.google.com/file/d/18-ig... لينك تليجرام https://t.me/mrahmedelbashagroup In This Part : The periodic table and electron configuration of elements Group Elements are similar in the number of electrons in the outermost energy level. Period Elements are similar in the number of energy levels occupied by electrons. Lewis Dot Structure for Valence Electrons Valence electrons: are the electrons in the outermost energy level Lewis proposed a simplified method to represent the number of electrons in the outermost energy level around an element's symbol known as valence electrons. These electrons are represented by dots (•) and are distributed around the symbol. Example: 16S The number of unpaired electrons in the Lewis structure = 2 So : the valence of sulfur is two. More Examples: How to determine the atomic number of elements of groups (A) by knowing their locations in the periodic table: بالتوفيق مستر احمد الباشا