1. The Structure of Matter
Chapter 5
The Structure of Matter

2. Electron Dot Diagrams
Short-hand way to show valence electrons

3. Steps to drawing Electron Dot Diagrams
Write out chemical symbol
Find the number of valence electrons
Draw the valence electrons in the configuration

4. Draw electron dot structures for elements 1-18

5. Compounds 2 or more elements that are chemically combined
Examples: H NaCl C6H12O6
Held together by chemical bonds
Have different properties that the elements that make them up
Always has same chemical formula no matter which state of matter

7. Chemical Bonding

8. Chemical bonds
Ionic
Covalent
Metallic

9. Ionic bonding
Electrons are gained or lost. One atom gains what another atom has lost.
Formed between opposite charged ions
Positive metals (cations) and negative nonmetals (anions)
Examples: CaCl2 NaCl MgO

11. Compounds that have ionic bonds:
Conduct electricity when dissolved in water
(b/c ions are then free to move)
Have high melting points
MgO

12. Naming ionic compounds
Includes names of all elements that are in the compound
Cations (+) uses same name
Example: NaCl (sodium chloride)
Anion (-) have altered names; drop ending and add “ide”
Example: CaCl2 (calcium chloride)

13. Practice: Name the following ionic compounds.
CaF2
KCl
BeS
K2S
MgS
CaI2

14. Writing ionic formulas
Identify type of bond that has occurred
Identify charges of ions
Balance charges using subscripts

15. Practice: Write the formulas for the following compounds.
Sodium flouride
Calcium oxide
Potassium sulfide
Lithium oxide
Beryllium chloride
Barium phosphide

16. Covalent bonds Formed between nonmetal atoms
Electrons are shared because nonmetals have like charges (both negative)
Oxygen

19. Properties of covalent bonds
Low melting points & Do NOT conduct electricity
More energy is needed to break triple bond than double, thus it’s stronger.

20. When electrons are shared equally called nonpolar covalent bonds
When atoms aren’t shared equally, they are attracted more to one nucleus than another, polar covalent bond

21. Naming Covalent compounds
1st element
has no prefix, if there is only 1 atom
If more than 1, use prefix to tell number of atoms
2nd element –
Changes ending to ‘ide’ suffix
Prefix tells number of atoms

22. Name these covalent compounds
BF3
N2O4

23. Write the Formula for the following compounds.
Sulfur dioxide
Silicon tetriodide
Tetraphophorus decoxide
Phosphorus trichloride

24. Polyatomic ions
Covalently bonded atoms that have lost or gained electrons
They can bond with compounds
Example: KNO3
They can bond with other polyatomic ions
Example: NH4NO3
Parenthesis show that it acts as one compound
Examples: (NH4)2SO4

25. Practice Writing the Formula Name
NaNO3
NaHCO3
(NH4)2SO4

26. Write the Formulas from the compound name.
Sodium nitrate
Lithium hydroxide
Ammonium chloride
Sodium carbonate
Potassium phosphate