1. CHEMICAL REACTIONS & CHEMICAL BONDING

2. ATOMS, MOLECULES, & COMPOUNDS Atoms- smallest part of an element.
Molecule- two or more elements
chemically combined. Same
or different type of atom.
ie.- O2, H2, H2O, CaCO3
Compound- two or more different types of
atoms chemically combined.
ie.- H2O, CaCO3, H2SO4

3. MOLECULES & COMPOUNDS

4. - Atoms want to fill their outer shell with
8 electrons.
- Electrons in the last (outermost) shell
are called valence electrons.
- Atoms will continue to react with one
another until their outer shell is full.
- Valence electrons let atoms bond with
other atoms.

5. VALENCE ELECTRONS

6. - The only exception to this rule is
Hydrogen & Helium since their
outer shell only holds 2 electrons.
Molecules can bond and “unbond” by
atoms being re-arranged in different
combinations.
- Chemical formula- (recipe), a combination
of symbols that represent the elements
in a compound.

7. FORMING CHEMICAL BONDS

8. WRITING CHEMICAL FORMULAS
To Write a Formula:
1. Write the symbols of the substances to be bonded.
2. Indicate the oxidation number of each substance.
3. Determine what multipliers are needed to equalize the charge.
4. Write the multiplier after each substance.
5. Write the positive substance first, the negative one second.
Example: Calcium and Nitrate
1. Calcium - Ca; nitrate = NO3
2. Ca = +2; NO3 = -1
3. Because 2 X -1 = 2, The multiplier for this formula is 2.
4. The subscripts are 1 and 2; Ca, and (NO3)2.
5. Ca (NO3)2 , or calcium nitrate.

9. CHEMICAL REACTIONS - Also known as a chemical change.
Occur when chemical bonds are
formed or broken.
yields
2Mg + O MgO
reactants
product

10. CHEMICAL EQUATIONS

11. EVIDENCE OF A CHEMICAL REACTION: - Color change - Precipitate forms
- Gas produced
- Temperature change
- Properties change.

12. CLASSIFICATION OF CHEMICAL REACTIONS:
Synthesis- “put together,” builds
compounds from simpler
substances.
A + B AB
Decomposition- breaks down compounds
into simpler substances.
AB A + B

13. EXAMPLES: Replacement- one element replaces another element in a
compound.
Single-
AB + C AC + B
A + BC AB + C
Double-
AB + CD AC + BD

14. CONTROLLING CHEMICAL REACTIONS: Every chemical reaction involves a
change of Energy.
Exothermic- releases energy in the
form of heat.
Endothermic- reaction takes energy
from the solution, to
make it feel cool.

15. ENDOTHERMIC REACTIONS
- endo- to the inside.
- therm- heat.
Reaction must take in Energy from
its surroundings to occur.
Energy is absorbed in the form of
heat, electricity, light, etc.

16. EXOTHERMIC REACTIONS - exo- to the outside. - therm- heat.
Energy is released as heat, light,
and sound.

17. ACTIVATION ENERGY Minimum amount of energy needed
that has to be added to start a chemical
reaction.
- This gets the reaction started.

18. ACTIVATION ENERGY
Energy is needed to begin a chemical
reaction.

19. RATE OF CHEMICALREACTIONS
Depends on how easily the particles
of the reactants can get together;
it is affected by:
- Concentration
- Surface area
- Temperature
- Catalyst
- Inhibitors

20. IONIC BONDING Ion is a positively or negatively charged atom.
Ions are created when an atom
gains or loses an electron when
they form a bond.
Attraction between two oppositely
charged ions. “Opposites attract”.
- Compounds are electrically neutral.

21. ATTRACTION NEEDED TO
FORM SALT

22. SALT- A BOND BETWEEN A
METAL & A NON-METAL

23. FORMING AN ION

24. PROPERTIES OF IONIC BONDS
- Forms very strong bonds.
- Dissolves in water.
- Often a solid at room temperature.
- Shatters or breaks, instead of bending.
Polyatomic ions- group of atoms
that acts as one.
Example-
(CO3)-2
(OH)-1

25. SALT IN SOLUTION
Salt (NaCl) forming Na+ and Cl- ions

26. IONIC BONDS - Naming Ionic Bonds: + ions (usually a metal) come first,
followed by the - ion.
If the - ion is an element, it will end
with the letters -ide.
example: NaCl Sodium chloride
If the - ion is a polyatomic ion the
ending remains the same.
example: CaCO3 Calcium carbonate

27. FORMULAS FOR IONIC
COMPOUNDS

28. COVALENT BONDING Formed when electrons are shared between atoms.
- Bond between 2 non-metals.
Both atoms attract the shared electron at
the same time.
- Can form double & triple bonds.

29. COVALENT BONDS

30. COVALENT BONDING

31. COVALENT BONDS
Valence
electrons
Single bonds
Double & Triple bonds

32. POLAR/NON-POLAR COVALENT BONDS
Polar bonds- some atoms pull stronger on shared electrons than others. As a result, electrons move closer to one atom,causing the atom to have a slight electric charge.
Non-polar bonds- pull on the atoms
equally.

33. Since water is a polar molecule it
attracts the Na+ and Cl- ions.

34. WATER- A POLAR COMPOUND

35. PROPERTIES OF COVALENT BONDS
- Often a liquid or gas at room temperature.
- Most don’t form crystals.
- Low melting temperature.
- Low boiling temperature.
- Poor conductors of electricity.

36. FORMULAS FOR COVALENT
COMPOUNDS