1. Chapter 2: Atoms and Bonding
Chemical Interactions
Chapter 2: Atoms and Bonding

2. Inside the Atom
Describe the structure of an atom and define protons, neutrons, and electrons.
Explain the role of valence electrons in forming chemical bonds.
Terms: nucleus, protons, neutrons, electrons, valence electrons, electron dot diagram

3. Inside the Atom Structure of an Atom
Atom made of nucleus surrounded by one or more electrons
Proton—positively charged
Neutron—neutral/no charge
Electron—negatively charged

4. Inside the Atom
Structure of an Atom

5. Inside the Atom Electrons in Atoms
Electrons are in an electron cloud around the nucleus
Little Particles, Big Spaces
Protons and neutrons make up most of the mass of an atom
Electrons make up most of the volume of the atom
Valence Electrons
Outer most electrons
Determines properties and bonding of an atom

6. Inside the Atom Models Dalton—solid ball Thomson—plum pudding model
Rutherford—electrons orbit around the nucleus
Bohr—electrons are in shells around the nucleus
Current model—nucleus surrounded by electron clouds

7. Inside the Atom
Lewis-dot Diagram
Dots represent valence electrons

8. Inside the Atom Why Atoms form Bonds
Atoms are more chemically stable with 8 valence electrons
Atoms gain or lose electrons in order to become chemically stable
Electrons can be given, accepted, or shared
When atoms interact new substance are formed

9. Atoms in the Periodic Table
Periodic Table: organized elements by increasing atomic number
Atomic Number: number of protons
Group/Family: vertical column on table
Have similar characteristics
Have same valence electrons
Period: horizontal row on table

10. Atoms in the Periodic Table
Periodic Table: organized elements by increasing atomic number
Atomic Number: number of protons
Group/Family: vertical column on table
Have similar characteristics
Have same valence electrons
Period: horizontal row on table

11. Atoms in the Periodic Table
Noble Gases
Group 18—inactive atoms
Reactive Nonmetals
Group 17-Halogens
Very reactive—need 1 electron
Reactive Metals
Group 1-Alkali Metals
Most reactive metals—give up 1 electron

12. Atoms in the Periodic Table

13. Atoms in the Periodic Table

14. Ionic Bonding Electron Transfer
Elements gain or lose electrons as they strive to have eight valence electrons
When an atom loses an electron—it becomes positive
When an atom gains an electron—it becomes negative
Ion: atom with a charge

15. Ionic Bonding Forming an Ionic Bond
Ionic Bond: attraction between two oppositely charged ions

16. Ionic Bonding Polyatomic Ions Naming Ionic Compounds
Ions made of more than one atom
Naming Ionic Compounds
Name of positive ion then name of negative ion
End of name –ide
For example: Sodium Chloride

17. Ionic Bonding Properties of Ionic Compounds
All have crystal shape, high melting points, and can conduct electricity
Formed between metals and nonmetals
Crystal Shape
3-D arrangements of ions called crystals
Ions are attracted to opposite charges and line up in rows
High Melting Points
Ionic bonds are strong and takes high energy/heat to break
Solid at room temperatures
Electrical Conductivity
Ions break up when dissolved in a liquid
Moving particles conduct electricity

18. Covalent Bonds Electron Sharing Formed when two atoms share electrons
Form between two or more nonmetals
Both atoms attract the two shared electrons at the same time

19. Covalent Bonds How Many Bonds? Properties of Molecular Compounds
Double Bond: form when two pairs of electrons are shared
Properties of Molecular Compounds
Created with covalent bonds
Lower melting points than ionic bonds
Most poor conductors of electricity