1. Chapter 2 Basic Chemistry

2. Matter and Energy
Matter – anything that occupies space and has mass (weight)
Physical vs Chemical changes
Energy – the ability to do work
Kinetic • Potential
Chemical • Electrical
Mechanical • Radiant
Law of Conservation of Energy- change forms

3. Composition of Matter Elements Atoms Fundamental units of matter
96% of the body is made from four elements
Carbon (C)
Oxygen (O)
Hydrogen (H)
Nitrogen (N)
Atoms
Building blocks of elements

4. Atomic Structure Inside nucleus
Protons (p+)
Neutrons (n0)
Outside nucleus in shells /clouds / or orbitals
Electrons (e-)
Valence e- (outside) determine chemical rxns

5. Identifying Elements Atomic number Atomic mass number
Equal to the number of protons that the atoms contain
Atomic mass number
Sum of the protons and neutrons

6. Atomic Weight and Isotopes
Isotopes – Carbon-12 and Carbon-14
Have the same number of protons
Vary in number of neutrons
Atomic weight
Close to mass number of most abundant isotope
Atomic weight reflects natural isotope variation

7. Radioactivity Radioisotope Radioactivity Heavy isotope
Tends to be unstable
Decomposes to more stable isotope
Radioactivity
Process of spontaneous atomic decay
Alpha, beta, gamma

8. Molecules and Compounds
Molecule – two or more like atoms combined chemically
Compound – two or more different atoms combined chemically
Carbon dioxide CO2

9. Chemical Reactions Atoms are united by chemical bonds
Atoms dissociate from other atoms when chemical bonds are broken

10. Electrons and Bonding
Bonding involves interactions between electrons in the outer shell (valence shell)
Full valence shells do not form bonds

11. Chemical Bonds 1. Ionic Bonds Ions - charged particles
electrons transferred from one atom to another
Ions - charged particles
Anions are negative (Cl-)
Cations are positive (Na+)

12. Chemical Bonds 2. Covalent Bonds Electrons are shared
Single covalent bonds share one electron
Double covalent bonds share two electrons

13. Examples of Covalent Bonds

14. Polarity Polar covalent bonds Non-polar covalent bonds
e- shared equally
No charge; neutral
Non-polar covalent bonds
e- shared unequally
Results in positive and negative sides
Have you bent water?

15. Carbon bonds Covalent bonds between two carbon atoms
Single bonds
Double bonds
Triple bonds
Quadruple bonds
Important for organic compds

16. Chemical Bonds 3. Hydrogen bonds Weak chemical bonds
Hydrogen is attracted to negative portion of polar molecule
Provides attraction between molecules

17. Patterns of Chemical Reactions
1. Synthesis reaction (A+BAB)
Atoms or molecules combine
Energy is absorbed for bond formation
Also called anabolic
2. Decomposition reaction (ABA+B)
Molecule is broken down
Chemical energy is released
Also called catabolic

18. Synthesis & Decomposition Reactions

19. 3. Exchange reaction (AB + C AC+B) single (AB+CD  AD+CB) double
Involves both synthesis and decomposition reactions
Switch is made between molecule parts and different molecules are made
Ex. Neutralization – acid/base reaction