2Stable Electron Configurations • When the highest occupied energy level of an atom is filled with electrons, the atom is stable and not likely to react. • Noble gases have stable configurations with full valence electrons.
3The chemical properties depend on the valence electrons. • Lewis created a model of showing the valence electrons– Called the Electron dot diagram, or also the Lewis Dot Structure.– Nitrogen, Group 5A
7Formation of IonsIn a neutral atom the number of protons is equal to the number of electrons.When an Ion is formed, the number of electrons is not equal to the protons.– It has an unbalanced charge called an ion.
8The charge is represented by a (+) or a (-) sign. The goal is to create stable atoms.
9Examples Chlorine has 17 electrons normally. – When it gains an electron it has 18, called an IONIt now has a charge of 1-.Written as Cl1-Negative Ions take the suffix “ide” in general.Chlorines Ion is Chloride
11Sodium ions have 11 protons and 10 electrons. One more proton than electron means it has a 1+ charge.Can be written as Na1+
12An ion with a positive charge is called a CATION
13When a cation and an anion are close together a chemical bond forms. The type of chemical bond is an IONIC BOND.
14Ionization EnergyThe amount of energy needed for an electron to move to a higher energy level.– Allows e- to overcome attraction of nucleus.– Takes more energy to remove e- from a nonmetal than a metal– Decreases down a group, increases across a period.
16Drawing Ionic Compounds Draw an example of this….. Magnesium Chloride. • 1. Draw electrons (dots) • 2. Move e- to most stable configuration • 3. Draw arrows to show new location • 4. Write the new charge of the ions formed