Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chemical Names & Formulas Chapter 9 Section 9.1 – Naming Ions Introduction • A rose is rosa in Spanish, warda in Arabic, and julab in Hindi. To truly understand another culture, you must first learn the language used in that culture. • Similarly, to understand chemistry, you must learn its language. For this you need to know how to name ions 1. Monatomic Ions • Monatomic ions consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons, respectively. • Cations: • When the metals in Groups 1A, 2A, and aluminum lose electrons, they form cations with positive charges equal to their group number • Aluminum is the only Group 3A metal. • The names of the cations of the Group 1A, Group 2A, and Group 3A metals are the same as the name of the metal, followed by the word ion or cation. Monatomic Ions (cont.) • Anions • The charge of any ion of a Group 5A7A nonmetal is determined by subtracting 8 from the group number. • Anion names start with the stem of the element name and end in -ide. • The majority of the elements in the two remaining representative groups, 4A and 8A, usually do not form ions. Monatomic Ions (cont.) • Ions of Transition Metals • Many of the transition metals (Groups 1B-8B) form more than one cation with different ionic charges. • The charges of the cations of many transition metal ions must be determined from the number of electrons lost. The colorful solutions contain the transition metal ions Co3+, Cr3+, Fe3+, Ni2+, and Mn2+. Monatomic Ions (cont.) • Two methods are used to name the ions of transition metals. 1. The Stock system • Preferred method • A Roman numeral in parentheses is placed after the name of the element to indicate the numerical value of the charge. 2. The Classical method • In an older less, useful method, the classical name of the element is used to form the root name for the element. • The suffix –ous is used to name the cation with the lower of the two ionic charges • The suffix –ic is used to name the cation with the higher of the two ionic charges 9.1 Monatomic Ions (cont.) • A few transition metals have only one ionic charge. • The names of these cations do not have a Roman numeral. • These exceptions include silver (Ag+), cadmium (Cd2+), and zinc (Zn2+) 2. Polyatomic Ions • Some ions, called polyatomic ions, are composed of more than one atom. • Polyatomic ions are tightly bound groups of atoms that behave as a unit and carry a charge. • The names of most polyatomic anions end in -ite or –ate when oxygen is one of the elements, called oxyanions. • Sometimes the same two or three elements combine in different ratios to form different polyatomic ions. • The charge on each polyatomic ion in a given pair is the same. • Ex. SO32- and SO42- Polyatomic Ions (cont.) • The –ite ending indicates one less oxygen atom than the –ate ending. • The ending does not tell you the actual number of oxygen atoms in the ion. • When the formula for a polyatomic ion begins with H, you can think of the H as representing a hydrogen cation combined with a polyatomic ion • The charge on the new ion is the algebraic sum of the ionic charges • Ex. HCO3- H+ + CO32• Polyatomic ions that begin with H are essential components of living systems END OF SECTION 1