1. Chapter 2
Basic Chemistry

2. Chemical Elements
2.1

3. Elements Matter- anything that takes up space and has mass.
Element- all matter, living and nonliving, are composed of these.
Each is unique (density, solubility, melting pt.)
92 naturally occurring elements

4. Elements 6 elements basic to life and make up 95% of body weight
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Phosphorus

6. Atoms
John Dalton and the atomic theory (elements consist of tiny particles called atoms)
Atoms- smallest unit of matter.

7. Subatomic Particles of Atoms
Neutrons- uncharged, in nucleus
Protons- positively charged, in nucleus
Electrons- negatively charged, around the nucleus in electron shells

9. Atomic Number and Mass Number
Atomic Number- number of protons in the nucleus
Mass Number- sum of the protons and neutrons in nucleus. Atomic Mass- average mass of all the isotopes for that element.

10. Isotopes
Atoms of the same element that differ in the number of neutrons.

11. The Periodic Table Horizontal rows called periods.
Vertical columns called groups.

12. Radioactive Isotopes This radiation can be detected in various ways.
Low Levels:
Can put small amount in a sample and it becomes a tracer to detect things.
Iodine 131 for thyroid
High Levels:
Harm cells, damage DNA, and cause cancer
Used to sterilize U.S. mail
Used to kill cancer cells.

13. Electrons and Energy
You cannot determine an electrons location, so we use Bohr model.
Electron shells or orbitals represent energy level electron is in.
1st shell- 2 electrons
2nd shell- 8 electrons
REGARDLESS of how many shells an atom has, the outermost is called the valence shell.

14. Electrons and Energy
Octet Rule- valence shell is most stable when it is full.
Atoms will give up, accept, or share electrons in order to become stable.

15. Molecules and Compounds
2.2

16. Molecules and Compounds
Molecule- two or more elements held together by a covalent bond.
Compound- molecule containing at least two different elements
A Formula tells you the number of each kind of atom in a molecule.

17. Ionic Bonding
Ionic compounds are held together by an attraction between negatively and positively charged ions.
One atom GIVES an electron to another atom in need thus becoming a compound.

18. Ionic Bonding

19. Covalent Bonding
Two atoms SHARE electrons in such a way that each atom has an octet of electrons in the outer shell.
Both are more stable because they SHARE an electron.

20. Covalent Bonding

21. Covalent Bonding
A double covalent bond occurs when two atoms share two pairs of electrons.

22. Nonpolar and Polar Covalent Bonds
Nonpolar- sharing is equal
Polar- when electrons are not shared equal. There is a “bully”

23. Chemistry of Water
2.3

24. Chemistry of Water
This shape and the polarity of water is formed because of hydrogen bonding.
Hydrogen bonding- attraction of a slightly positive H to a slightly negative atom in vicinity.

25. Chemistry of Water
Dotted lines show hydrogens are attracted to other oxygen atoms.
These bonds are easier to break.
H bonds also happen in DNA (steps to the ladder)

26. Chemistry of Water Living things are 70-90% water. Freezes at 0˚C
Boils at 100˚C
Calorie- amount of heat energy needed to raise temp of 1 g of water.
Water also has high heat evaporation.

27. Water Is a Solvent Dissolves lots of things.
Solution- contains dissolved substances.
If something attracts water it is hydrophilic
If it repels water it is hydrophobic.
Can cling together and can cling to other POLAR substances.

28. Acids and Bases
2.4

29. Acids and Bases
pH 7- neutral state in which the hydrogen ion and hydroxide ion concentrations are equal.
Below 7- acidic
Above 7- basic

30. Acids and Bases
Buffer- is a chemical or a combo of chemicals that keeps pH within normal limits.