Daily Science (on periodic table) Using different colors, color in (with a crayon or colored pencil) the different families of the periodic table. You should have the following families colored: Alkali Metals Alkaline-Earth Metals Transition metals Semi-conductors Non-metals in groups 14-16 Metals in groups 13-16 Halogens Noble gases *Be sure to include a key on the back of your periodic table or on the last sheet in your notebook.

Forming Compounds and Molecules Pg. 57

Chemical Bonds The forces that hold atoms or ions together are chemical bonds.

Chemical Structure We use 3 models to show chemical structure Ball-and-stick model: Show the bond length and bond angle Atoms are balls and bonds are sticks Space-filling model: Shows the space that the atoms take up Structural formula: Chemical symbols are used to represent atoms

Ball and Stick Model

Structural Formula

Space-filling model

Bonding Atoms bond when their valence electrons interact. Atoms bond so that they satisfy the octet rule There are 4 different types of bonds: Ionic Covalent Metallic Hydrogen

Ionic Bonds Formed from the attraction between oppositely charged ions. Formed between cation (positively charged) and anion (negatively charged). Non-metal + metal Formed by the transfer of electrons Some atoms have more of an attraction for electrons. This is called electronegativity. When melted or dissolved, they conduct electricity. Ex. NaCl

Covalent Bonds Electrons are shared They don’t usually conduct electrons Nonmetal + nonmetal More than one electron can be shared creating double and triple bonds

Metallic Bonds Called “sea of electrons” Can conduct electricity Atoms are so closely packed that the outer energy levels overlap. Usually occurs with transition metals

Hydrogen bonds Occur between hydrogen and either: Oxygen Nitrogen Fluorine This is why some bugs can glide on top of water.

Polyatomic Ions Some compounds have ionic and covalent bonds They act as a single unit Parenthesis group polyatomic ions together The subscript on the outside of a polyatomic ions applies to the whole ion Ex: (NH4)2SO4