Mr. Bouyer

Day 1 | Day 2 | Day 3 | Lab | Vocabulary Test

vocabulary for the week
  • Chemical bond
  • Valence electron
  • Ionic bond
  • Ionization
  • Ionication energy
  • Electron affinity
  • Covalent bond
  • Diatomic molecule
  • Polyatomic ion
  • Metallic bond
  • Electron-dot diagram
  • Orbital-filling diagram

Chemical Bonding

link to a local webpage What determines the type of bond that forms between atoms?

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Cosmetologist
 Some atoms will interact to combine and from new substances. Atoms that interact in this way are said to be chemically "bonded". Whether atoms will interact to form chemical bonds depends almost entirely on their electron arrangement.
atom

The electrons in the outer energy level can be called valence electrons. It is these electrons that determine the formation of chemical bonds. There are certain numbers of valance electrons that are more stable than others. Atoms will gain or lose electrons in order to become more stable. Atoms with eight valence electrons are the most stable.

Types of chemical bonds:link to an Internet Website

  1. Ionic bonds - electrons are transferred between atoms.
    • One atom gains electrons while another atom loses electrons.
    • When this happens, the charges within each atom are no longer balanced.
    • The atoms have become ions - one with a positive charge, the other with a negative charge.
    • The force of attraction between these opposite charges holds the ions together in an ionic bond.

    • Ionization - the process of removing an electron from an atom to form an ion.
    • Ionization energy - the energy needed to remove an electron from an atom. For this to occur, the attraction between the negatively charged electron and the positively charged nucleus must be overcome.
    • Electron affinity - the tendency of an atom to attract electrons. This characteristic determines the type of bond formed between atoms.
      • Metals generally have a low electron affinity.
      • Nonmetals generally have a high electron affinity.

  2. Covalent bonds - electrons are shared between atoms.
    • Atoms that do not lose electrons easily but attract electrons usually form covelent bonds.
    • The positive nucleus of both atoms has an equal attraction for the electrons being shared.
    • The shared electrons spend most of their time between the two atoms.
    • It is the attraction between the nucleus and the shared electrons that holds the atoms together.

    • Diatomic molecules. When found in nature a pure elements, these seven elements exist only as two atoms covalently bonded.
      • Hydrogen - H2
      • Nitrogen - N2
      • Oxygen - O2
      • Florine - F2
      • Chlorine - Cl2
      • Bromine - Br2
      • Iodine - I2
    • Polyatomic ion - a group of covalently bonded atoms that acts like a single atom when combining with other atoms. Overall, this group of atoms is not electrically balanced and does have a total charge.

  3. Metallic bonds - electrons are distributed equally through a metallic crystal.
    • The electrons in metals can be thought of as being property of all the atoms.
    • The positive nuclei are surrounded by a "sea of electrons" that are all attracted by the nuclei at the same time.

Computer Assignment 121:
This assignment must be completed by the beginning of class tomorrow to receive credit.
Scoring criterialink to a local webpage

PowerPoint is a "presentation graphics" program. It is used to visually provide information to a group of people - not just one person sitting in front of a computer. Color combinations and font size must make the slides easily read from a distance.

  1. Use a new PowerPoint slide with the layout that has a title block and a blank page.
    1. Title this slide as "The 7 Diatomic Molecules".
    2. Paste this Periodic Table link to a local webpage onto the slide.
    3. Put a size 4 green line around the box on the table containing each of the diatomic molecules.
  2. Use a second PowerPoint slide with the same layout as #1.
    1. Title this slide as "Ionic Bonding".
    2. Use PowerPoint tools to draw a Bohr model of a hydrogen atom on the left of the slide and a Bohr model of a chlorine atom on the right.
    3. Duplicate this slide. Then use motion on the new slide to show what happens to the electron of the hydrogen atom when the compound HCl is formed.

    Save this PowerPoint file on your computer and show it to your science facilitator.


Physical Science

 

 

 

 

 

 

 

   

 

Electron affinity determines the type of bond that forms between atoms.
Atoms with similar attraction for electrons will form covalent bonds. Atoms with different attraction for electrons will form ionic bonds. No bonds are purely covalent or ionic. Think of bonds as having a percentage of each.