Warm Up  Find the charges on the following ions: 6.Ca 7.As 8.Al 9.He 10.Mg 1.H 2.I 3.O 4.Kr 5.B

Density  Density is the ratio of an objects’ mass to its volume  Units: g/cm 3 or g/mL

Density  If a piece of gold has a density of g/cm 3 and a volume of 10 cm 3, what is its mass?  D x V = M  g/cm 3 x 10 cm 3 = g

Naming Binary Ionic Compounds  The name of a compound must distinguish it from other compounds made of the same elements.  Ionic compounds follow the pattern of:  Cation anion -ide  Cation: positively charged ion (the metal)  Anion: negatively charged ion (the nonmetal)  Atom: Iodine Ion: Iodide

Naming Binary Ionic Compounds  Name the following ionic compounds:  NaCl  Li 3 N Sodium chloride Lithium nitride

Writing Chemical Formulas for Ionic Compounds  Steps for writing the chemical formula for a binary ionic compound:  Write the cation (metal) first anion (nonmetal) second  Find the charge for each ion using the periodic table  “Criss-cross” the charges—write the charge of each ion as the number of atoms of the other element.

Writing Chemical Formulas for Ionic Compounds  Write the chemical formula for the following ionic compounds:  Sodium fluoride  NaF  Magnesium bromide  MgBr 2

Naming Covalent Compounds  The most metallic metal is first in the name  Most metallic=to the left on the periodic table  Prefixes tell the number of atoms of each element.  If there is only one atom of the first element, there is no prefix. CO = carbon monoxide not monocarbon monoxide

Naming Covalent Compounds Number of AtomsPrefix 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa- 7Hepta- 8Octa- 9Nona- 10Deca-  Name the following compound: P2O5P2O5  Diphosphorous pentaoxide

Writing Chemical Formulas for Covalent Compounds  Write the chemical formula for the following compound:  Sulfur trioxide  SO 3

Law of Conservation of Matter  According to the law of conservation of matter, matter is neither created nor destroyed.  This means we must have the same number and type of atoms after the chemical change as were present before the chemical change. 2H → 2H 2 0

Balancing Chemical Equations Cu + O 2 → Cu0  Step 1: take an inventory—write which elements and how many atoms of each are on each side  Step 2: Add coefficients to balance the equation ReactantsProducts ReactantsProducts Cu = 1 O = 2O = 1

Balancing Chemical Equations Cu + O 2 → CuO ReactantsProducts Cu = 2 O = 2  The coefficient multiplies all of the elements in the molecule by that number  2MgF 2 has 2 atoms of Mg and 4 atoms of F  Never change the subscripts (the little numbers beside the elements) 2Cu + O 2 → 2CuO

Types of Chemical Reactions  Synthesis  Decomposition  Single Replacement  Double Replacement

Worksheet Academic expectations: Review and learn density, naming ionic and covalent compounds, writing their formulas, and balancing equations in preparation for EOC May Work alone or in groups. Complete by the end of class or finish for homework. Behavior expectations: Speak at volume that can only be heard at your table. Stay in your seat or ask for permission if you need to get up.

Closure  Class discussion:  Of the topics we went over today, which do you think will be the most important when you take chemistry in high school and/or college? Why?