Ionic compounds are formed by ionic bonding between two different atoms. In this type of bond, one of the atoms (usually that of a metal) loses one or more electrons and the other atom (usually that of a non-metal) accepts the electron/s. The naming of ionic compounds reflect it. According to the naming nomenclature of ionic compounds, metal is named first, followed by the name of non-metal (ending in -ide, such as chloride, nitride, oxide, etc.). In case of transition metals, we also include the number of valence electrons in roman numerals, such as iron (II) oxide, etc.
Covalent compounds are formed by sharing of electrons between different atoms. Here, electrons are drawn towards the more electronegative atom, but are not completely donated by the less electronegative atom. Typically non-metals form covalent compounds. According to the naming nomenclature, we write the name of the non metal that appears furthest to the left of the periodic table first, followed by the name of the other non-metal (ending in -ide, such as chloride, oxide, etc.). We also use prefixes to state the number of participating atoms, such as di for 2 and tri for 3. Some examples are dinitrogen trioxide, carbon tetrachloride, carbon dioxide, etc.
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