Warm-up • What is the name of CO? a. Carbon dioxide c. Oxygen Carbon b. Carbon oxide d. Carbon monoxide • What is the name of K2O? a. Potassium oxide c. Krypton oxygen b. Potassium dioxide d. Krypton oxide • • • • What are isotopes? What are alpha particles? What are beta particles? What are gamma rays? Naming Ionic or Covalent Compounds Naming Ionic and Covalent compounds follow different rules We will begin by learning the rules of naming ionic compounds first. Naming Ionic Compounds 1. Start with the name of the first atom in the molecule. 2. Take the next atom in the molecule and replace its ending with an “ide” suffix. 3. Putting those two names together gives you the compound’s name. That is why NaCl is called Sodium chloride. It gets more complicated but for now stick with the rules. • The first atom of an ionic bond is the cation (PAWsitively) and then follow with the anion. • The anion will contain the first syllable of the element name and end with the suffix -ide Naming Covalent Compounds You will be expected to have the following memorized because you will need to know the prefixes for naming covalent compounds. Prefix Meaning Prefix Meaning mono one hexa six di two hepta seven tri three octa eight tetra four nona nine penta five deca ten These prefixes are inserted before each name in the compound to indicate how many of each type of atom are the molecule. However if the prefix used on the first atom is “mono”, we drop it. Example of naming a covalent compound CO2 has the name carbon dioxide. Since there is only one carbon in the molecule we should use the name mono before carbon. But we drop mono and just say carbon. However we have to put a “di” prefix in front of oxygen because we have 2 oxygen atoms present. Just like naming the ionic compounds, we change the last atom’s name to an “ide” ending. Dihydrogen Monoxide • BAN DIHYDROGEN MONOXIDE - THE INVISIBLE KILLER! • Dihydrogen monoxide is colorless, odorless, tasteless, and kills uncounted thousands of people every year. • What are the dangers of Dihydrogen Monoxide? • Most of these deaths are caused by accidental inhalation of DHMO, but the dangers of dihydrogen monoxide do not end there. Prolonged exposure to its solid form causes severe tissue damage. Symptoms of DHMO ingestion can include excessive sweating and urination, and possibly a bloated feeling, nausea, vomiting and body electrolyte imbalance. For those who have become dependent, DHMO withdrawal means certain death. • What is your solution to this dangerous problem? Example Name the compound whose chemical formula is AL2O3 This is not a covalent bond because AL lies on the left of the zigzag line it is a metal. Thus this is a ionic bond. We simply name it aluminum oxide. Example What is the name of the molecule PH3 Since P and H are both non metals this is a covalent bond. The prefix for phosphorus (P) is “mono” but since it is the first atom we drop the mono. The prefix for hydrogen is tri and don’t forget to add the ide to the end of hydrogen. So we name this phosphorus trihydride. Quick Check Name the following compounds 1. SF6 2. K3N 3. P2O3 4. CaCl2 Give the chemical formulas for the following covalent compounds. 5. Oxygen dichloride 6. dicarbon dihydride Quick Check answers Name the following compounds 1. SF6 sulfur hexafluoride 2. K3N potassium nitride 3. P2O3 diphosphorus trioxide 4. CaCl2 calcium chloride Give the chemical formulas for the following covalent compounds. 5. Oxygen dichloride 6. dicarbon dihydride OCl2 C2H2 Warm-up: Table of Half-lives Element Phosphorous Polonium Radium Sodium Uranium 24 215 226 24 238 Half-life 14.3 days 0.0018 seconds 1600 years 15 hours 4.5 billion years If 1 g of sodium-24 has decayed from a sample that was originally 2 g, how old is the sample? Number of 0 years after of • Table formation 1600 3200 6400 12800 50% 25% 12.5% 6.25% Remaining Radium Percent of 100% radium-226 remaining A scientist has a 2.5 g sample of radium-226. How many grams of the sample will decay in 800 years? • How is the periodic table organized? • What are isotopes? • What is the difference between nuclear fission and fusion?