Ions Monatomic Ions Ion Formulas and Names 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 (has similar properties..) 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 12 protons 12 electrons Mg2+ ___ protons ___ electrons ___ isoelectronic O2- ___ protons ___ electrons ___ isoelectronic O 8 protons 8 electrons

Why is lithium oxide Li2O Ionic bonding: Li + O Why is lithium oxide Li2O 3p+ 4n0 2e-1e- 8e- 2e- 8n0 8p+ 3p+ 4n0 2e- 1e- 6e- 2e- 8n0 8p+ 3p+ 4n0 2e-1e- 1e- O Li [ O ]2– [Li]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+ P3- Fe3+ 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 S2- Pb2+ Ba2+ Cr4+ Al3+ C4-

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 Name polyatomic ions. -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.

Ag+ 7. Cu+ 8. NH4+ 9. P3- 10. Cl3+

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. Polyatomic ions. Remaining anions. (These will be anything left that ends in –ide). Remaining ions containing a Roman Numeral. Remaining ions without a Roman Numeral. (Groups 1 & 2, silver, cadmium, zinc, aluminum).

6. Hydroxide ion 7. Cadmium ion 8. Lithium ion 9. Calcium ion 10. Mercury (I) ion