Ionic and Metallic Bonds Chapter 8 Section 3 Ionic and Metallic Bonds

Ions An ion is an atom that is no longer electrically neutral because it has gained or lost electrons. An ion that loses electrons becomes POSITIVE The protons are in greater number An ion that gains electrons becomes NEGATIVE The electrons are in greater number

Losing Valence electrons Example- Na Sodium has 1 valence electron because it is in Group 1 If it loses that 1 electron then it would have 10 electrons which is the same as Neon Neon is a Noble gas so it has 8 valence electrons and is chemically stable Metals give up electrons

Gaining valence electrons Non metals are both good at sharing electrons and receiving them from Metals Example- Cl has 7 valence electrons It just needs 1 more to become stable and have 8. Na can give it 1 so that it can be like Argon- a noble gas Na becomes Na¹ and Cl becomes Cl¹¯

Determining an ions charge To determine the charge on an ion Subtract the number of electrons from the number of protons

Ionic bonds Metals lose electrons to non metals Metals become positively charged and the non metal becomes negatively charged These ions attract each other to form an ionic compound and an ionic bond The attraction between positively and negatively charged ions in an ionic compound is an Ionic bound.

Characteristics of ionic compounds Solid and brittle at room temperature Relatively high boiling and melting points Usually dissolve in water to become a good conductor of electricity

Metallic bonds Metal atoms can bond to other metal atoms They pool their valence electrons A metallic bond is formed when many metal atoms share their pooled valence electrons

Properties of Metallic bonds Good conductors of thermal energy and electricity Can be hammered into sheets because the electrons can slide over each other Shiny because the valence electrons reflect light