Transcript The Chemistry of Life

The Chemistry of Life
Atoms and Elements
Chapter 6
Atoms are
the basic
units of all
matter.
An atom is the
smallest particle of
an element that has
the characteristics
of that element.
•
Atoms are composed of
3 sub-atomic particles:
The nucleus is the center of an
atom.
•The nucleus contains positive
protons (+) and neutral neutrons
(0).
The electron cloud is the area
surrounding the nucleus
•it contains negative electrons (-).
An element is a substance that can not
be broken down into simpler chemical
substances.
Each element is identified by a one- or
two-letter abbreviation called a symbol.
Atomic number
The atomic number is equal to
the number of protons that an
atom has.
Ex. Silver has an atomic number
of 47 and therefore has 47
protons
Atomic mass
The atomic mass is the number
of protons and neutrons added
together.
How do you figure how many
neutrons there are?
Atomic mass - atomic number =
number of neutrons!
Atoms of the same element that have
different numbers of neutrons are called
isotopes.
Isotopes still have the same chemical
properties as the element!
Ex: Carbon normally has 6p, 6n, and 6e. This is C-12
(carbon 12).
But wait! Carbon can also have 7 or 8 neutrons!
*These would be C-13 and C-14.
Ions
If an atom loses/gains electrons,
it becomes an ION and will have
a charge
Ex. Na+1 (lost an electron)
Cl -1 (gained an electron)
Do you want to hear a funny joke??
Fun fact:
Carbon,
hydrogen,
oxygen, and
nitrogen are the
four elements
that make up
more than 96%
of the mass of a
human body