Transcript Ion?
Chapter 10 & 7A Ions Monatomic Ions Ion Formulas and Names Ion Vocabulary • An ion is an atom or group of atoms that have a charge. • A cation is a positive ion. • An anion is a negative ion. If a neutral atom loses one or more electrons it becomes a cation. Na 11 protons 11 electrons Na+ 11 protons 10 electrons If a neutral atom gains one or more electrons it becomes an anion. Cl 17 protons 17 electrons Cl- 17 protons 18 electrons Atoms tend to lose and gain electrons when they bond with other atoms in an attempt to become more stable. Why is Na+ more stable than Na • Na = 1s22s22p63s1 Why is Na+ more stable than Na • Na = 1s22s22p63s1 Lose 1 e• Na+ = 1s22s22p6 Why is Na+ more stable than Na • Na = 1s22s22p63s1 Lose 1 e• Na+ = 1s22s22p6 • This is isoelectronic with Ne Why is Clˉ more stable than Cl • Cl = 1s22s22p63s23p5 Why is Clˉ more stable than Cl • Cl = 1s22s22p63s23p5 Gain 1 e• Clˉ = 1s22s22p63s23p6 Why is Clˉ more stable than Cl • Cl = 1s22s22p63s23p5 Gain 1 e• Clˉ = 1s22s22p63s23p6 • This is isoelectronic with Ar Determine the number of protons and electrons for each ion and state what noble gas each is isoelectronic with. Mg O 12 protons 12 electrons 8 protons 8 electrons Mg2+ O2- ___ protons ___ electrons ___ isoelectronic ___ protons ___ electrons ___ isoelectronic Ionic bonding: Li + O Why is lithium oxide Li2O 3p+ 2e-1e4n0 1e6e- 2e- 3p+ 2e-1e4n0 Li Li 1e- O 3p+ 2e4n0 8e- 2e- 8p+ 8n0 8p+ 8n0 3p+ 2e4n0 [Li]2+ [ O ]2– Ion Vocabulary • A monatomic ion is an atom with a charge. • The charge on a monatomic ion is called an oxidation number. • A polyatomic ion is a group of atoms with a charge. Types of monatomic ions and the rules for naming them • The periodic table is useful in naming the monatomic ions. Monatomic cations with one oxidation number • The cations from the periodic table which have a single oxidation number are as follows: Group 1 (+1), Group 2 (+2), Ag+, Cd2+, Zn2+, and Al3+. • These types of ions are named by using the name of the element followed by the word ion. • Na+ sodium ion • Ba2+ barium ion • Zn2+ zinc ion • We can use the roman numeral from the periodic table to identify the oxidation number for these ions. Monatomic cations with multiple oxidation numbers • All other cations that are not listed in the previous category (“cations with one oxidation number”) are considered to have the possibility of multiple oxidation numbers. • These type of ions are named by using the name of the element followed by a Roman numeral to indicate the oxidation number. • Cu2+ copper (II) • Pb4+ lead (IV) • Mn7+ manganese (VII) • It is important to note that the roman numerals in these names may or may not be the roman numeral from the periodic table. • All atoms other than F or the noble gases can form positive ions. Negative Monatomic anions • All anions from the periodic table are named by changing the ending of the element’s name to –ide. • F- fluoride ion • O2- oxide ion • N3- nitride ion • Count back from the noble gases starting at zero to determine the oxidation number. Ask Yourself 3 Questions. Does the name end with: Ion? Roman numeral? -ide? Name these monatomic ions • • • • • • Rb+ P3Fe3+ Br‾ Mn4+ Cd2+ Rubidium ion Phosphide Iron III Bromide Manganese IV Cadmium ion Write the formula for these monatomic ions. • • • • • • Sulfide Lead (II) Barium ion Chromium (IV) Aluminum ion Carbide S2Pb2+ Ba2+ Cr4+ Al3+ C4- •Can skip the next three slides if time is running short. Atoms of elements and Ions of elements are different Atoms of elements Sodium is a soft, silvery highly reactive metal. It is used in making light bulbs and for heat exchange in nuclear reactors. A pale yellow-green gas, chlorine killed soldiers in WWI. Today it primarily used to kill bacteria in water. Ions of elements Combined together sodium and chlorine make common table salt and are thus essential to life. Table salt consists of sodium ions (Na+) and chloride ions (Cl-) Steps for Naming Ions 1. Name polyatomic ions. 2. -ide, ion, Roman numeral? • Name remaining anions (change ending to –ide) • Name remaining cations from groups 1, 2, Ag+, Cd2+, Zn2+, Al3+. (use the name of the element and add “ion”) • Name all remaining cations using the name of the element followed by a roman numeral equal to the positive charge of the cation. 1. 2SO4 2. O 2- 7. Cu+ 2+ 3. Mg 4. Pb 6. + Ag 8. NH4+ 2+ 9. 3P 5. NO2 - 10. 3+ Cl 1. 2- SO4 sulfate 2- 6. Ag+ silver ion 7. Cu+ copper I 2. O oxide 3. 2+ Mg magnesium ion 8. NH4+ ammonium 4. Pb2+ lead II 5. - NO2 nitrite 9. P3- phosphide 10. Cl3+ chlorine III Steps for Writing Formulas of Ions • Many people find that they wish to do these in the order that they are presented. You can however do them in 4 sets. 1. Polyatomic ions. 2. Remaining negative ions: (–ide). 3. Remaining positive ions: Roman Numeral or Ion. 1. Cobalt (I) ion 6. Hydroxide ion 2. Selenide ion 7. Cadmium ion 3. Phosphite ion 8. Lithium ion 4. Nitrogen (V) ion 9. Calcium ion 5. Arsenide ion 10. Mercury (I) ion 1. Cobalt (I) ion Co+ 6. Hydroxide ion OH- 2- 7. Cadmium ion Cd2+ 2. Selenide ion Se 3. Phosphite ion PO3 3- 8. Lithium ion Li+ 5+ 9. Calcium ion Ca2+ 4. Nitrogen (V) ion N 5. Arsenide ion As3- 10. Mercury (I) ion Hg22+ Homework • Lab Summary “Tap Water Test” (You do not need to copy entire “Objective Section” as your purpose). Due Wednesday (12/2/15). • Worksheet: Ions: Due Thursday 12/3/15). • Ions Quiz (includes names and formulas of both monatomic and polyatomic ions) will be shortly after returning from Break.