Ionic Compounds and Naming of Ionic Compounds Chapter 7

Objectives 1. SWBAT identify cations and anions. 2. SWBAT calculate the number of protons, neutrons, and electrons in different ions. 3. SWBAT to predict the ion the atom will most likely form.

IONS https://www.youtube.com/watch?v=900dXBWgx3Y

Electron Ionization ← Sodium Atom The process by which an atom acquires a negative or positive charge by gaining or losing electrons to form ions Their ionic charges are determined by how many valence electrons they lose or gain in order to become stable ← Sodium Atom

Ions An atom with an electrical charge A valence electron is gained or lost Occurs 2 ways: Oxidation – loss of an e- results in a (+) charge Reduction – gain of an e- results in a (-) charge

Ions H+ (lost 1 e) As3- (gained 3 e) Cl- (gained 1 e) Mg2+ (lost 2 e) Oxidation State – Number found on the periodic table Shows the number of e- gained or lost Many elements have more than one number

More about Ions Cation – positive ion Anion – negative ion Monatomic ions (or monatomic) Polyatomic ions Na+, Cl- Na+, Cl-, Mg2+, O2-, Al3+, N3- NH4+, CO32-, SO42-, PO43-

Polyatomic Ions A charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. Poly = Many (Greek)

DO NOW Name the following Polyatomic Ions 1. O22- 2. CN- 3. IO3-

DO NOW Number of Neutrons Number of Neutrons Fe3+

Number of Neutrons Number of Neutrons 9 10 9 9 Fe3+ 26 26 23 29 12 12 10 12

Ions and Ionic Compounds Molecules make up one kind of Molecular compound. Ions make up another kind of compound, called Ionic Compounds

https://www.youtube.com/watch?v=zpaHPXVR8WU Ionic Compounds Oppositely charged ions connect together to form ionic compounds. For example, sodium ions (Na+) connect to chloride ions (Cl-) to make sodium chloride (NaCl), or table salt. 17

Sodium chloride consists of an equal number of positive and negative ions arranged in a 3-dimensional network called a crystal. A scanning electron micrograph shows the cubic structure of NaCl crystals.

Formulas for Ionic Compounds 3 Rules for Writing Formulas for Ionic Compounds 1. Cation first, then anion 2. Correct formula will be neutral, with the fewest number of each ion needed to make the total electrical charge zero (no charges shown) 3. Have the last few letters changed to –ide (monoatomic ions only) Ex. KF, potassium fluoride Ex. Ca(NO3)2, calcium nitrate

Practice Problems NaCl  Sodium Chloride One Na1+ and one Cl1- cancel each other out. (+1 + -1 = 0) CaCl2  Calcium Chloride One Ca2+ needs two of the Cl1- to cancel it out. (+2 + -1 + -1 = 0) Note: Negative monoatomic ions change their ending to “ide.” Examples above are sodium chloride and calcium chloride.

Formulas Containing Polyatomic Ions Formulas for compounds containing polyatomic ions follow the same rules If a subscript is needed, it follows the entire polyatomic ion, which is enclosed in parentheses

Formulas Containing Polyatomic Ions For example, the calcium ion has a +2 charge (Ca2+) and the nitrate ion has a -1 charge (NO31+). Two nitrate ions are needed to balance out the charge on one calcium ion. The formula for calcium nitrate is: Ca(NO3)2 Polyatomic ions do not change their endings (so no IDE).

DO NOW Name the following compounds or write the correct formula: MgO = Iron (III) Chloride = Cr2(SO4) 3 = Calcium Nitrate =

DO NOW: Write the formula and name the following ionic compounds 1. Ca2+ Br- 2. PO43- Ag+ 3. CO32- NH4+ 4. Al3+ NO3- What does the word “ionic” mean?