8 - Unit 1, Section 1 - Day 4

• Protons and electrons are balanced in an atom

  • That means there are an equal number of protons and electrons

• Atoms are neutral (they have zero charge

Atoms - Balanced Protons and Electrons

• Ion - An atom that has an electric charge

  • They can be positive or negative

• Ions form when there are an unequal number of protons and electrons

Ions

• Ions form when an atom either loses or gains electrons

• Atoms do not lose or gain protons to form ions

How do Ions form?

• Negative ions

• Formed when atoms gain electrons

Anions

• Positive ions

• Formed when atoms lose electrons

Cations

An ion's charge is determined by how many electrons it loses or gains

Ionic Charge and The Periodic Table

Ionic Bonding - the attraction between a positive cation and a negative anion

• This attraction is in three dimensions

• A crystal forms with alternating cations and anions

Ionic Bonding

Ionic bonding usually happens when a metal and a nonmetal interact

• The metal loses electrons and becomes a cation

• The nonmetal gains electrons and becomes an anion

• The cation and anion are attracted to each other and form a crystal

Ionic bonding and the Periodic Table