Interactions of Matter Text Chapter 1 Chemical Bonding

What is chemical bonding? The joining of atoms to form new substances. The joining of atoms to form new substances. Properties are different from original substances. Properties are different from original substances. Chemical Bond- the interaction that holds the atoms together. Chemical Bond- the interaction that holds the atoms together. Electrons can be shared, lost, or joined. Electrons can be shared, lost, or joined.

Let’s Review! How are the electrons organized in their energy levels? How are the electrons organized in their energy levels? Atomic Number = the number of protons Atomic Number = the number of protons Neutral atom… protons = electrons Neutral atom… protons = electrons Energy Levels of electrons…Bohr Model Energy Levels of electrons…Bohr Model Nucleus = protons + neutrons Nucleus = protons + neutrons 2 electrons in the 1 st shell maximum 2 electrons in the 1 st shell maximum 8 electrons in the 2 nd shell maximum 8 electrons in the 2 nd shell maximum 18 electrons in the 3 rd shell maximum 18 electrons in the 3 rd shell maximum 32 electrons in the 4 th shell maximum 32 electrons in the 4 th shell maximum 56 electrons in the 5 th shell maximum 56 electrons in the 5 th shell maximum

What do electrons have to do with bonding? Valence electron- an electron in the outermost shell. Valence electron- an electron in the outermost shell. The family number on the top of the column of the Periodic table can tell you how many valence electrons an atom has. The family number on the top of the column of the Periodic table can tell you how many valence electrons an atom has. Atoms that have less than 8 valence electrons like to bond. Those that have 8 do not bond. This is called the Octet Rule. Atoms that have less than 8 valence electrons like to bond. Those that have 8 do not bond. This is called the Octet Rule.

What kinds of bonds are there? Ionic Bonds Ionic Bonds Covalent Bonds Covalent Bonds Metallic Bonds Metallic Bonds

What are Ionic Bonds? Electrons are transferred from one atom to another in order to have full outer shells. Electrons are transferred from one atom to another in order to have full outer shells. When electrons are exchanged, the atoms become charged. They are NOT neutral anymore. When electrons are exchanged, the atoms become charged. They are NOT neutral anymore. Ions- charged particles are formed when atoms gain or lose electrons. Ions- charged particles are formed when atoms gain or lose electrons. More electrons than protons = negative ion More electrons than protons = negative ion Less electrons than protons = positive ion Less electrons than protons = positive ion

What are Ionic Compounds? When ionic bonds form, and the ions are charged, positive and negative, they form a strong attraction. (ex. Magnets) When ionic bonds form, and the ions are charged, positive and negative, they form a strong attraction. (ex. Magnets) This is called a crystal lattice- a repeating 3 dimensional pattern. This is called a crystal lattice- a repeating 3 dimensional pattern. Properties can include: brittleness. High melting points, and high boiling points. Properties can include: brittleness. High melting points, and high boiling points.

What are Covalent Bonds? Occur when atoms share one or more pairs of electrons (also called molecules) Occur when atoms share one or more pairs of electrons (also called molecules)

How are they represented? Electron –dot Diagrams or Lewis Structures Electron –dot Diagrams or Lewis Structures

What are Metallic Bonds? Bond formed by the attraction between positively charged metal ions and the electrons in the metal. (This is why metal can be shaped- malleable and ductile. Also gives the property of conductivity.) Bond formed by the attraction between positively charged metal ions and the electrons in the metal. (This is why metal can be shaped- malleable and ductile. Also gives the property of conductivity.) Even though they are surrounded by positive charges and should repel, they are attracted to the electrons in the metal (which are negative); therefore, metals bend and are not brittle. Even though they are surrounded by positive charges and should repel, they are attracted to the electrons in the metal (which are negative); therefore, metals bend and are not brittle.