Download Chemistry Introduction

Introduction to Chemistry
Bio-Chemistry
“The Chemistry of Life”
1
The Atomic Theory
• All matter (living and non-living)
found on Earth is composed of
atoms.
2
The Atomic Theory
• In the following video, please
define the following terms:
–amu
–isotope
3
Introduction to Chemistry
4
Basic Chemistry
• Atom: Smallest particle an
element can be divided into.
• Parts of the Atom:
– Proton: positive charge, in nucleus.
– Neutron: no charge, in nucleus.
– Electron: negative charge, around the
nucleus.
5
Atom
• Is now defined as the smallest particle of
an element that retains the chemical
properties of that element.
Electrons
Nucleus
(protons
and neutrons)
Animation: Subatomic
Particles
PLAY
ANIMATION
Basic Chemistry
• Element: A pure substance or
material composed of only one type
of atom.
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Periodic Table of Elements
9
The Periodic Table
• The periodic table is broken down into vertical column
called groups or families numbered from left to right (118) and…
• horizontal rows called periods numbered from top to
bottom (1-7)
Types of Elements
• For the most part you can divide
the periodic table into two main
parts, Metals and Non-metals.
Metals
• Metals are located of the left side
of the table and make up
approximately 88% of all elements.
• Are generally good conductors of
both heat and electricity.
• Most are solids as well as
malleable and ductile.
Nonmetals
• Are located on the right side of the
periodic table and comprise
approximately 12% of all elements.
• Are poor conductors of electricity
and heat, tend to be brittle, and are
often (though not always) found as
gases in nature.
Metalloids
• Are elements that have some characteristics
of metals and also some non-metal
characteristics.
• They are located along the “stair step” line
on the right side of the periodic table.
• All are solids, are less malleable than metals
but not as brittle as non-metals.
• Tend to be semi-conductors of electricity.
Noble Gases
• Found in group 18 of the periodic
table.
• Generally un-reactive.
• Gases at room temperature.
Basic Chemistry
• Molecule:
– Atoms make up molecules.
– Two or more atoms bonded together.
• One type of atom (ex: O2)
• Two or more types of atoms (ex: H2O)
16
Basic Chemistry
• Compound:
– Atoms make up compounds.
– Two or more elements bonded together.
• Two or more types of atoms (ex: H2O)
17
Basic Chemistry
• Atomic Number:
– The number of Protons in the
nucleus of an atom of a particular
element.
18
Basic Chemistry
• Atomic Mass:
– The number of Protons + the number
of Neutrons in the nucleus of an
atom of a particular element.
19
6
C
Carbon
Atomic Number
Symbol
Name
12.011
Average atomic mass
2
2
[He]2s 2p
Electron configuration
Isotopes
Atoms of the same element (the
same number of protons) with
different numbers of neutrons.
They have identical atomic numbers
but different mass numbers.
ISOTOPES
The Four Most Common
Elements in Living Matter
•
•
•
•
Atomic Number 6 - Carbon
Atomic Number 1 - Hydrogen
Atomic Number 8 - Oxygen
Atomic Number 7 - Nitrogen
23
Assignment
• Complete 5-1 (p. 18) & 5-2 (p. 21)
in your Cell & Cell Processes lab
manual.
• Review Programmed reading…it is
fair game on a quiz…hint, hint
24
Electron Energy Levels
2
3
4
1
• Within the electron cloud,
electrons are arranged in
“energy levels”.
• Electrons in each energy
level have a specific amount
of energy
• Each energy level can only
hold a specific number of
electrons.
Atomic Structures
Combinations
• Few elements
exist as
independent
particles, most
substances are
made up of
combinations
of atoms held
Octet Rule
• “Eight is great”
• The outer valence shell can hold a
maximum of 8 electrons
• Achieving the maximum number of
e- in this valence shell results in a
stable “content” atom.
28
Chemical Bond
A mutual
electrical
attraction
between the
nuclei and
valence
electrons of
different atoms
Why Atoms Bond to Other Atoms
Most atoms are less stable existing by
themselves (they are at a relatively high
potential energy). Nature favors
arrangements in which potential energy is
minimized. Bonding creates more stable
arrangements of matter in lower potential
energy states. (Mama Nature doesn’t like to
sweat!).
Bonding
• Valence electrons
are redistributed.
Two main types:
Covalent
Ionic
Types of Chemical Bonding
Ionic
vs.
Covalent
• Electrical attraction between
cations and anions.
• Sharing of electron
• Due to gain or loss of
pairs between atoms
electrons (also called
• H2
electron transfer) between
atoms.
• H2O
Animation: Atomic Number,
Mass Number
PLAY
ANIMATION
Ions
• An ion is an atom or group of atoms with
one or more net positive or negative
electrical charges.
• The number of positive or negative charges
on an ion is shown as a superscript after the
symbol for an atom or group of atoms
– Hydrogen ions (H+), Hydroxide ions
(OH-)
– Sodium ions (Na+), Chloride ions (Cl-)
Animation: Ionic Bonds
PLAY
ANIMATION
Electron Dot Notation
An electron configuration notation in
which only the valence electrons of an
atom of a particular element are
shown, indicated by dots placed around
the element’s symbol.
Lewis Structures
• Using electrondot notation to
represent
molecules.
G. N. Lewis
1875 - 1946
Lewis Structures
• Formulas in which
atomic symbols represent
nuclei and inner-shell
electrons, dot-pairs or
dashes represent electron
pairs in covalent bonds,
and dots adjacent to only
one symbol represent
unshared electrons.