Chapter 15Ionic Bonding and Ionic CompoundsDIRECTIONS: COPY ONLY THE UNDERLINED INFO!
Ionic Bond Bond formed between a metal and nonmetal.
Why do atoms bond? • Atoms bond in order to acquire a full set of valence electrons. • Most of the time this is 8 . This is known as the octet rule. • Atoms will gain, lose or share in order to attain a full set of electrons
Valence Electrons • The electrons responsible for the chemical properties of atoms are those in the outer energy level. These electrons are called the valence electrons. • Valence electrons - The electrons in the outer energy level
Keeping Track of Electrons • Atoms in the same column... • Have the same valence electrons. • LABEL!
Electron Dot diagrams • A way of keeping track of valence electrons. • How to write them? • Write the symbol. • Put one dot for each valence electron • Don’t pair up until they have to (Hund’s rule) X
The Electron Dot diagram for Nitrogen • Nitrogen has 5 valence electrons. • First we write the symbol. N • Then add 1 electron at a time to each side. • Until they are forced to pair up.
Write electron dot diagrams: • Na • Mg • C • O
Electron Configurations for Cations • Metals lose electrons to attain noble gas configuration. • They make positive ions (cations) • If we look at the electron configuration, it makes sense to lose electrons: • Na 1s22s22p63s1 1 valence electron • Na1+1s22s22p6 noble gas configuration
Electron Configurations for Anions • Nonmetals lose electrons to attain noble gas configuration. • They make negative ions (anions) • If we look at the electron configuration, it makes sense to lose electrons: • F 1s22s22p5 2 valence electrons • F-1 1s22s22p6 noble gas configuration
Properties of Ionic Compounds • A regular repeating arrangement of ions in the solid: this is known as a lattice. Structure is rigid. • High melting points
Do they Conduct? • Conducting electricity is allowing charges to move. • In a solid, the ions are locked in place. • Ionic solids are insulators. • When melted, the ions can move around. Therefore, they have the ability to conduct electricity • Ionic Compounds dissolved in water conduct