Ionic Bonds And Ionic Compounds Section 7.2 Ionic Bonds And Ionic Compounds

Formation of an Ionic Bond Compound A chemical combination of two or more different elements Binary compounds when there are exactly two different elements

Na + Cl  Na+ + Cl- + energy P. 210 shows chemical reactions that form ionic bonds and release energy Sodium and chlorine gas produce a white crystalline solid Na + Cl  Na+ + Cl- + energy This is called a chemical equation.

What Happened? + Sodium transferred one valence electron to chlorine. [Na]+ + [Cl]- + energy + This is the electron-dot structures

Types of Ionic Compounds Electrostatic force holds the charged atoms together is the ionic bond. Metal and non-metal ionic bond are called oxides. Most other ionic compounds are called salts.

Names Sodium + Chlorine forms sodium chloride Sodium is a metal Chlorine is a non-metal Change chlorine to chloride in the name of the compound

p. 210 b Ribbon of magnesium metal burns in air, it forms the ionic compound magnesium oxide. Magnesium is a metal Oxygen is a non-metal Notice the name, oxygen became oxide. Is this a binary ionic compound?

Questions Explain how an ionic compound forms from these elements sodium and nitrogen lithium and oxygen strontium and fluorine aluminum and sulfur

Properties of Ionic Compounds Physical structure Ratio of positive and negative ions Ions are packed into repeating pattern * No single unit of Na and Cl exists, there are many Na+ and Cl- ions in a 1 to 1 ratio.

Question What determines the ratio?

Common Ionic Compounds Carpet: calcium carbonate Ceramics/glass: calcium carbonate, lithium borate, magnesium silicate, sodium carbonate Glossy Paper: aluminum silicate, calcium carbonate, sodium sulfate, calcium oxide, sodium carbonate, titanium(IV) oxide Toothpaste: calcium carbonate, sodium carbonate, sodium-hydrogen carbonate, sodium fluoride

Crystal Lattice Three dimensional geometric arrangement of particles Each positive ion is surrounded by negative ions and each negative ion is surrounded by positive ions The number of ions and the ratio determine the size and shape

Examples Minerals More than 1/3 of all known minerals are silicates Halides Borates Carbonates What elements do you think are in these?

Physical Properties Melting point - high Boiling point - high Hardness - hard, rigid, brittle solids, hard to break apart Depends on the strength of the ionic attraction Conduct electricity Solids: ions are locked into place, cannot conduct electricity Melt or dissolve solids into solutions, the yes Electrolytes are solutions that conduct electricity and important to humans

Energy Endothermic Energy is absorbed Exothermic Energy is released Formation of ionic compounds Forms more stable system so lower energy state, release energy

Lattice Energy Energy required to separate 1 mol of the ions in an ionic compound The greater the lattice energy, the stronger the force of attraction ( harder to separate)

Summary Ionic compounds contain ionic bonds formed by the attraction of oppositely charged ions. Ions in a ionic compound are arranged in repeating patterns known as a crystal lattice. Ionic compounds properties are related to ionic bond strength.

Ionic compounds are electrolytes; they conduct an electric current in the liquid phase and in aqueous solution. Lattice energy is the energy needed to remove 1 mol of ions from its lattice.

Questions Explain how an ionic compound made up of charged particles can be neutral? Describe the energy change associated with ionic bond formation, and relate it to stabillity. Identify three physical properties of ionic compounds that are associated with ionic bonds, and related them to bond strength.

Explain how ions form bonds, and describe the structure of the resulting compound. Relate lattice energy to bond strength. Use electron configurations, orbital notations and electron dot structures to represent the formation of an ionic compound from the mental strontium and the non-metal chlorine.

Question Using the elements aluminum and oxygen, determine the formula for the ionic compound. Extension: Use Fe2+ and Fe3+ to combine with O2- Determine the formula for the ionic compounds.

Each Student List a metal and a non-metal Exchange papers and determine the ionic compound formed between them.

Exit Ticket Determine the ionic compound formed from Mg and Cl and explain how it was formed. Include its ratio