Basic chemistryWhy learn it?

Life depends on chemistry. If the first task of an architect is to understand building materials, then the first job of a biologist is to understand the chemistry of life.

Where?

Chapter 2 of your textbook

What?

In order:

1.The basics: Atoms and Compounds (small)

2.Properties of Water

3.Macromolecules (big)

4.Enzymes: how they get things done

I anticipate a number of lab activities, at least 1 project, and 1 vocab assignment. There will also be some small homework assignments.

Atoms

• Atoms – The basic unit of matter. Atoms are very small, made up of subatomic particles that are even smaller than the atom. Atoms are usually neutral, meaning they have no charge.

Protons

• Protons-       Have about the same mass as a neutron.      Have a positive charge       Contained in nucleus in the center of the atom

• Atoms have the same number of protons as electrons

Neutrons

• Neutrons       Have about the same mass as a proton.      Have no charge = neutral

• Contained in nucleus in the center of the atom

Electrons• Electrons      Negatively charged particle      Electrons are in constant motion      They move around the out side of the nucleus      Atoms have the same number of protons as

electrons      Electrons are in orbits around the nucleus      The first orbit can hold 2 electrons

• The second orbit can hold up to eight electrons

Element

• Element-       is a substance composed of only one

type of atom      more than 100 elements      Elements are represented by one or two

letter symbol• Sum of protons and neutrons in nucleus is

called atomic mass

Periodic Table

• Atomic Number - Simply refers to the number of protons present in the atom.

• Element Symbol - This is the symbol that chemical formulas or equations use to indicate that certain element.

• Atomic Mass - The average mass of one atom of that element in amu's (Atomic Mass Units).

Compounds

Chemical compounds       Substance formed by two or more elements       Formed in definite proportions       Properties of compound is different that the

elements its formed by       Hydrogen and oxygen are gases at room

temperature, when combined they form water, a liquid, at room temperature.

Bonding

Chemical Bonds-      Atoms in a compound are held together

by chemical bonds      Bonds are formed by the electrons in

the area around the nucleus

• The electrons that are available to from bonds are called valence electrons

Bonding

Covalent bonds      Strongest bonds      Shared electrons

 

•Two electrons are shared 

Single covalent Bond

      Double covalent bond

•Four electrons are shared 

Ions

• Ions      Ions are formed by giving up or

receiving an electron      Ions can have a positive charge or

negative charge      If atom gives an electron it has a

positive charge called a Cation• If atom gains an electron it has an negative

charge called an Anion

Ionic Bonds      Formed when one or more electrons are transferred from one atom to the other

  

Isotopes

• Isotopes-  Have different number of

neutrons  They have the same

number of electrons & protons

• All chemical properties such as bonding remain the same

Van der Waals Forces

• Van der Waals Forces  Not all electrons are shared equally when

bonds are formed  When sharing is unequal, one end of a

molecule may be slightly more positive or negative than the other

  A slight attraction between molecules can develop because of oppositely charged regions

Van der Waals forces