Transcript The Nature of Matter

The Chemistry of Life
The Nature of Matter
Atoms!!!
Building Block of Elements
 Contains a nucleus = center
 Has Energy Levels surrounding the
outside
 Each atom is distinct for each individual
element

Atomic Structure
The protons and neutrons make up a
concentrated core= NUCLEUS
 The electrons are in constant motion
circling the nucleus near the speed of
light!!

Parts of the Atom
Protons: positive charge; nucleus
 Neutrons: no charge; nucleus
 Electrons: negative charge, around
nucleus in levels or shells

Elements
Made of the same kind of atoms
 Cannot be broken down
 90 elements occur naturally on earth
 They can all be found on the PERIODIC
TABLE.

THE PERIODIC TABLE
Reading the Periodic Table
Left to Right, Top to Bottom
 All elements are represented
by symbols
*They increase in increments of 1

*atomic number= # of protons
*atomic mass= protons + neutrons
Consider The Following…
Atomic #
Atomic Mass
27
58.9
Co
Element
Name
Cobalt
Atomic
Symbol
What is an Isotope?

Atoms of the same element that have
different numbers of NEUTRONS.

The same elements will ALWAYS have
the same number of protons.
Ex: Carbon 12 and Carbon 14
Find The Difference!
http://web.visionlearning.com/custom/chemistry/animations/
CHE1.3-an-isotopes.shtml
Note and explain the difference between the
atoms shown!
Link courtesy of vision learning!
What is an Ion???


An atom that has either lost or gained an
electron from it’s outer most shell and taken on a
charge
Valence Shell = Outer Most Shell

+ = loss of an electron
- = gain of an electron

Ex: Na+, Ca 2+ , Cl -

Compounds
Two or more elements bonded together
 Almost all substances in “nature” occur as
compounds
 When elements combine to make
compounds, they LOSE their original
properties.


Ex: H2O, CO2, and HCl
Types of Bonds
Bonding= 2 or more elements either
sharing or stealing electrons
 Takes place in the OUTER MOST energy
level


Who you bond with depends on the
number of electron vacancies in the
valence shell
Rules of Molecular Bonding
1.
2.
3.
All atoms want to achieve STABILITY.
Stability = FULL Valence Shell
However many electrons you need or
can give away determines “who” you
bond with.
COVALENT BONDS

formed when 2 atoms share electrons in
the outer most energy level forming a
molecule with NO CHARGE

Classic Example: Water!!!
IONIC BONDS

2 oppositely charged ions attract each
other, forming a neutral bond (canceling
each other out)

Classic Example: Sodium Chloride
= Table Salt
For Example

Chlorine= 17 electrons
2-first shell 8-second shell 7-third shell
(holds 8)
so, Cl needs one more e- to be stable
SODIUM

Na has 11 e-, which means…
2 first shell 8 second shell
only 1 in third shell (holds eight)
So, Na needs to LOSE one e-!!!
Why Do They Bond?