bonding

• Covalent bonds involve sharing pairs of electrons between atoms.
• Covalent bonds occur between nonmetals, where both atoms share electrons equally.
• Ionic bonds are formed when electrons are transferred from one atom to another.
• Ionic bonding occurs when one atom transfers electrons to another atom, resulting in the formation of positive and negative ions.
• Metallic bonds occur when metal atoms lose their outermost shell electrons and form a sea of delocalized electrons that hold the positively charged metal ions together.
• Metal atoms lose electrons to form positive ions (cations), while non-metal atoms gain electrons to form negative ions (anions).
• Ionic compounds are formed when one atom loses an electron to another atom.
• Covalent bonding is a type of bonding between two or more atoms where electrons are shared.
• Covalent bonds are strong and require a lot of energy to break.
• The simplest example of covalent bonding is between hydrogen atoms, where both atoms have one electron in their outer shell, so they share one electron each to give them both a full outer shell.
• When drawing covalent molecules, we use "dot cross diagrams" as we do with ionic compounds.
• It is important to represent the electrons on one atom with a dot and on the other atom with an X.
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• The first five examples of covalent bonding, hydrogen, chlorine, water, hydrogen chloride and ammonia (NH3), all share one electron per atom in a to make a full outer shell of electrons on each atom.
• Some atoms need more than one electron to give them a full outer shell, for example, oxygen needs 2 electrons to complete its outer shell.
• Oxygen shares two electrons per atom to make a double bond.
• Nitrogen needs three electrons to complete its outer shell, this forms a triple bond between the two nitrogen atoms, to make a nitrogen molecule.
• A molecule is a substance which contains two or more covalently bonded atoms.
• A lone pair is a pair of electrons that are not part of the covalent bond.
• Covalent bonds are strong because there is an attraction between the electrons in the covalent bond and the positively charged nucleus, meaning a lot of energy is required to break a covalent bond.
• Simple covalent compounds have low melting points and are often gases at room temperature, for example, oxygen and carbon dioxide.
• Although the covalent bonds between the atoms in simple covalent compounds are strong, the intermolecular forces between the molecules are weak, meaning only a small amount of energy is required to overcome these weak forces.
• Fluorine is a gas at room temperature because it is a small molecule, while astatine is a solid at room temperature because its molecules are larger.
• There are several ways to represent ionic bonding, including dot and cross diagrams, 2D ball and stick model of ionic bonding, and 3D Ball and Stick model of ionic bonding.
• Ionic compounds have high melting points due to strong electrostatic forces between the oppositely charged ions.
• Ionic compounds do not conduct electricity as a solid but do conduct electricity if they are dissolved in water (aqueous) or in the liquid state.
• Ionic bonding occurs when a metal atom reacts with a non-metal atom, transferring electrons from the metal atom to the non-metal atom, resulting in a positive charge on the metal atom and a negative charge on the non-metal atom.
• The empirical formula of an ionic compound is the simplest ratio of atoms in a compound.
• Ionic compounds have properties similar to those of noble gases, with a full outer shell.
• Polymers are very large molecules, made from monomers.
• The size of the intermolecular force between molecules increases as the molecules get larger.
• The repeating unit is the shortest repeating section of a polymer.
• As you go down group 7, the boiling points increase because the molecules get larger.
• Ionic compounds have regular structures, known as giant ionic lattices, in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions.
• Metals are elements which lose electrons to form positive ions.
• Ions are atoms with a positive or negative charge, formed by an atom gaining or losing electrons.