Title: Combining Matter Page #: 23 Date: 10/15/12

Objective Students will be able to describe chemical bonds that unite atoms to form compounds. Students will be able to relate the nature of chemical bonds that hold compounds together to the physical structures of compounds.

Words of the Day Energy Level - Where electrons are located. Valence Electrons - Electrons located in the outermost energy level of an atom.

Combining Matter Idea*** - Atoms combine through electric forces, forming molecules and compounds. Compound: A substance that is composed of 2 or more different elements. Examples: H O = 2Hs + 1O NaCl = 1Na + 1Cl 2

Combining Matter Most compounds have different properties from the elements of which the are composed. H O is a liquid > H and O by themselves are gasses. 2

Combining Matter Chemical Formulas: The way a compound is named. Composed of the symbol for each element, followed by a subscript #, that indicates the # of atoms in the compound. If there is only 1 atom of an element in a compound, there is no subscript number. H O = 2Hs + 1O 2 Subscript

Combining Matter Chemical Bonds: The force that holds elements in a compound together. An atom is stable when its outermost energy level is full. ***Atoms want to be stable!***

Combining Matter Covalent Bond - When two atoms are held together by sharing 1 or more electrons (atoms can only share their valence electrons.) Example: Hydrogen e˜ e˜ e˜ e˜ Not bonded Bonded

Combining Matter Classwork: Drawing placement of valence electrons. Using your periodic table, draw configuration of Ne H Si Li C O N