Tiêu đề EDX Topic 5 bonding.pdf ✅

Topic 6 Bonding & Structure 1
Topic 6 What is meant by an ion? 2 Bonding & Structures Bonding & Structures Atoms of most elements undergo chemical reactions and form bonds. They lose, gain or share electrons to have full outer shells and become stable. Why? To reach the electronic configuration of the nearest noble gas. Noble gases are unreactive (inert) because they are stable, they have full outer shells of electrons. Cation: a positively charged ion that has more protons than electrons. Anion: a negatively charged ion that has more electrons than protons. Types of Bonding Ionic Covalent Metallic Between metals and non-metals, it involves loss and gain of electrons Between non-metals, it involves sharing of electrons inside a metal element It’s an electrically charged atom that lost or gained electrons to become stable. Define How atoms form ions? Sodium is an element in group 1; it has an electronic configuration of 2,8,1 To obtain full out shell electrons it loses 1 electron to another atom and forms a positively charged ion (Na+) with a charge of +1
3 Oxygen is an element in group 6; it has electronic configuration 2,6. To obtain full outershell electrons it gains 2 electron from another atom , and it forms a negatively charged ion (O-2) With a charge of -2 Valence Electrons: electrons in the outer shell of an atom. E.g. Sodium has one valence electrons & chlorine has 7 valence electrons. Valency: is the number of electrons lost or gained by an atom to become stable. E.g. Sodium loses 1 electron its valency is 1 & chlorine gains 1 its valency is 1. Important Ionic Bonding Ionic Bonding Metals react with non-metals to form an ionic compound. Metal atoms loses electrons and forms a positive ion. Non-metal atoms gain electrons & form a negative ion with name ending in -ide. Positive and negative ions attract each other, and are arranged in a lattice as they have opposite charges. The compound has no overall charge. Ionic Bond: strong electrostatic force between positive & negative ions Topic 6
4 Example 1 Ionic Bond between Sodium and Chlorine to form Sodium Chloride (NaCl) Sodium atom loses 1 electron forming positive sodium ion and transfers this electron to chlorine. Chlorine atom gains 1 electron forming chloride negative ion. The two ions have opposite charges, so they attract each other. Example 2 Ionic Bond between Magnesium and Oxygen to form Magnesium Oxide (MgO) Magnesium atom loses 2 electrons forming Mg2+ and transfer them to an atom oxygen Oxygen atom gains 2 electrons forming O2- The two ions have opposite charges, so they attract each other. Topic 6