1 / 24

Notes P.1-2

Notes P.1-2. January 22, 2014. Objectives. You will be able to: Define metallic, ionic, and covalent bonds and explain their characteristics State if two atoms will form a covalent or ionic bond Write ionic formula units . Overview of bonding.

vanya
Download Presentation

Notes P.1-2

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. Notes P.1-2 January 22, 2014

  2. Objectives • You will be able to: • Define metallic, ionic, and covalent bonds and explain their characteristics • State if two atoms will form a covalent or ionic bond • Write ionic formula units

  3. Overview of bonding • Chemical bond: mutual electrical attractionbetween the nuclei and valence electrons of different atoms that binds those atoms together. • Why do atoms bond? • Most atoms are more stable when they are bondedthan they were as individual atoms

  4. Types of chemical bonds: • Metallic – seaofelectrons • Occur between: between metals • Ionic – stealelectrons • Occur between: metal—nonmetal • Covalent – shareelectrons • Occur between: nonmetal—nonmetal • Covalent or Ionic? • Determined by electronegativity difference

  5. Remember: Metallic Character NONMETALS (IN GREEN) METALS (IN YELLOW)

  6. Practice • Label as ionic, covalent, or metallic: NaF CaBr2 H2S Al2O3 Cu NO3 Ionic Ionic Covalent Ionic Metallic Covalent

  7. METALLIC BONDING • Results from the attraction of nuclei to a “sea of electrons”

  8. Sea of Electrons

  9. METALLIC BONDING • Why an “electron sea”? • Vacant p and d orbitals in metal's outer energy levels overlap, and allow outer electrons to move freely throughout the metal • Valence electrons do not belong to any one atom

  10. METALLIC BONDING • Common properties of metals: • High melting/boiling points • Conduct heat and electricity • Have luster (shiny) • Ductile/malleable • All thanks to the electron sea!

  11. IONIC BONDING • Results from the electrical attraction between cations and anions • Cation: + • Anion: -

  12. The resulting ions come together due to electrical attraction (opposites attract)

  13. IONIC BONDING Common Properties: • Solid crystals at room temperature • Very high melting/boiling points • (Most) Can dissolve in water • Conduct electricity when melted or dissolved

  14. Ionic Formula Units • The net (total) charge on the compound must equal zero • Positive and negative cancel out • Hint: Use the criss-cross method

  15. Ionic Formula Units EXAMPLES: • Na and Cl • Na and O • Caand O • Caand Cl • Aland O

  16. Ionic Formula Units EXAMPLES: • Na and Cl  Na+ + Cl-  NaCl • Na and O Na+ + O2-  Na2O • Caand O • Caand Cl • Aland O

  17. Na and O Na2O means that: Two sodium cations are needed to balance one oxygen anion.

  18. Positive and negative charges must cancel each other out EXAMPLES: Total +Total -Net • Na+ and Cl- NaCl 1 1 0 • Na+ and O2-  Na2O2 2 0 • Ca2+and O2- CaO 2 2 0 • Ca2+and Cl- CaCl22 2 0 • Al3+and O2-  Al2O36 6 0

  19. Crystal Lattice • A network of alternating cations and anions

  20. Ionic compounds The formula for ionic compounds does not show the exact number of atoms that are bonded together. The formula tells the smallest whole number ratio of atoms that bond.

  21. COVALENT BONDING • Results from the sharing of electron pairsbetween two atoms (each has a full valence shell) • A covalent compound is called a molecule

  22. Each has a full octet

  23. COVALENT BONDING • Common properties of covalent compounds: • Low melting/boiling points • Many are liquids or gases at room temp • Non-conductors of heat and electricity

  24. Can you…? • Define metallic, ionic, and covalent bonds and explain their characteristics? • State if two atoms will form a covalent or ionic bond? • Write ionic formula units? • Homework 6A, Due Friday • Lab on Friday

More Related