1 / 15

Chemical Bonding

Chemical Bonding. Sections 1-3 Pages 4-21. Combining Atoms through Chemical Bonding. Chemical Bonding : joining of atoms to form new substances. Properties of these new substances are different from the original elements

Download Presentation

Chemical Bonding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chemical Bonding Sections 1-3 Pages 4-21

  2. Combining Atoms through Chemical Bonding • Chemical Bonding: joining of atoms to form new substances. • Properties of these new substances are different from the original elements • An interaction that holds two atoms together is called a chemical bond. • When a chemical bond forms, electrons are shared, gained or lost.

  3. Electron Number and Organization • Electrons organized in energy levels (orbits, clouds, shells) • Atomic number tells you how many electrons (and protons) • Atoms form bonds using electrons in outermost energy level. An electron in the outmost energy level is a valence electron.

  4. Valence Electrons and the Periodic Table • Elements are grouped according to their properties and have the same number of valence electrons. • Most groups (1, 2, 3-18) all have a way to determine their number of valence electrons based on their group number (except Helium)

  5. To Bond or Not to Bond? • Valence electrons determine if an atom bonds. • Group 18 usually does not bond because their outer shell is full because it has 8 electrons. Octet rule. • Atoms gain, lose or share electrons to obtain a full outer shell.

  6. Forming Ionic Bonds • An ionic bond is a bond that forms when electrons are transferred from one atom to another. • During ionic bonding, one or more electrons are transferred from one atom to another to fill that atom’s outer level. • Usually metals.

  7. Ions (forming charged particles) • Positive Ions (lose an electron) • Groups 1 and 2 (metals) • Energy needed • Symbol has a + (ex. Na⁺ or Ca²⁺) • Negative Ions (gain an electron) • Groups 16 and 17 (non metals) • Energy gained • Symbol has a - (ex. Cl⁻ or O²⁻)

  8. Ionic Compounds • When ionic bonds form the charge becomes neutral. • They form a crystal lattice (orderly 3D pattern) which gives the compound certain properties (brittleness, high melting points and high boiling points)

  9. Covalent Bonds • Substances with covalent bonds tend to have low melting and boiling points and are brittle when in solid state • Covalent bond forms when atoms share one or more pairs of electrons • If two nonmetal atoms were to lose electrons it would require a lot of energy, so the two nonmetal atoms don’t transfer electrons…they share instead. • When they share equally they are called Nonpolar covalent bonds. NO charge. • When they share unequally they are called polar covalent bonds. Slight charge. • Usually nonmetals.

  10. Covalent Bonds and Molecules • The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons. • A molecule usually consists of two or more atoms joined in a definite ratio

  11. Using Electron Dot Diagrams • An electron dot diagram is a model that shows only the valence electrons. • Write the symbol, then place one dot around the symbol for every valence electron. • Place the first 4 dots alone on each side, then pair up any remaining dots.

  12. Simple Molecules- Diatomic Molecules • Diatomic Molecules:molecules made up of two atoms of the same element • Diatomic Elements: elements that are found in nature as diatomic molecules • Examples: H, O, N, and the Halogens

  13. Metallic Bonds • A metallic bond is a bond formed by the attraction between positively charged metal ions and the electron in the metal • Positively charged metal ions form when metal atoms lose electrons. • The positive metal ions are in fixed position in the metal. • The negative electrons are free to move. • This allows metals these properties of malleability, ductility and electrical conductivity.

  14. Types of Chemical Bonds

  15. Bonding Animation • http://www.bsc2.ehb-schweiz2.ch/Chemie/Simulationen%20Chemie/Bindung/Bindung%20Hundeanalogie.htm

More Related