1. The Nature of Matter

2. Atoms Atoms: the basic unit of matter
electrons: outside of the nucleus; negative charge
protons: inside the nucleus; positive charge
neutrons: inside the nucleus; neutral

3. Elements
Element: pure substance that consists of only one type of atom.
1 or 2 letter symbol
Atomic Number: # of protons
Atomic Mass: # of protons + neutron. 6 C
12.011

5. Isotopes element with the same number of protons and electrons
different number of neutrons
same chemical properties
Radioactive Isotopes: their nuclei are unstable and break down at a constant rate
the radiation that is release can be dangerous

6. Compounds
Compound: the combination of two or more elements,; water, glucose, and methane
Atoms are held together by chemical bonds.
Smallest unit of a compound is a molecule.
H2O C6H12O6 CH4

7. Types of Chemical Bonds
Ionic Bonds
Covalent Bonds

8. Ionic Bond occur between a metal and a nonmetal
transfers electrons
lose electrons  positive
gain electrons  negative
ion: positively or negatively charges species
Na+ + Cl-  NaCl (table salt)
F K+ S2-

9. Ionic Bond

10. Covalent Bonds Covalent Bonds: occur between two nonmetals
share electrons
share 2 electrons: single bond
share 4 electrons: double bond

11. Covalent Bond

12. Van der Waals Forces
attraction to oppositely charged regions of two atoms
weaker than ionic or covalent bonds
gechos: can climb vertical surfaces