Download Atomic structure

THE CHEMISTRY OF
LIFE
Section 2.1: The Nature of Matter
Adapted from Teacher: Mrs. Rolle
Atomic Structure
Atomic Structure
ELECTRON –
negative, mass
nearly nothing
NEUTRON –
neutral, same
mass as
proton (“1”)
PROTON –
positive, same
mass as
neutron (“1”)
The Atom
Nucleus
Shell or Orbit
Electron
If all atoms are made of protons, neutrons,
& electrons, why do different atoms have
different chemical properties?
Answer- It’s dependent upon the number
and the arrangement of…
• Electrons!
• Electrons are the parts of atoms that
are affected by chemical reactions!
• Atoms of different elements have
different numbers of electrons,
protons, and neutrons!
Differentiating Atoms
• Atomic Number
• Number of protons in
the nucleusdetermines the type
of atom
• Since atoms are
electrically neutral,
the number of
protons = number of
electrons
• Mass Number
• Number of protons +
neutrons in the
nucleus
• Usually very close to
the atomic mass BUT
it’s not the same
thing!
• Protons + neutrons=
mass
The Atom Hydrogen
Proton
Electron
Hydrogen has one proton, one electron and NO neutrons
The Atom Helium
Proton
Electron
Neutron
Helium has two electrons, two protons and two neutrons
Mass and atomic number
Particle
Proton
Relative Mass
1
Relative Charge
1
Neutron
Electron
1
0
0
-1
PROTON NUMBER = number of
protons (obviously)
SYMBOL
MASS NUMBER = number of
protons + number of neutrons
The Atom Helium
Proton
Electron
Neutron
Helium has two electrons, two protons and two neutrons
The Atom Lithium
Protons
Neutrons
Electrons
The Atom Beryllium
Protons
Electrons
Neutrons
Beryllium has four electrons, four protons and five neutrons.
The Atom Boron
Protons
Neutrons
Boron has five electrons, five protons and six neutrons.
Electrons
The Atom Carbon
Protons
Neutrons
Carbon has six electrons, six protons and six neutrons.
Electrons
The Atom Nitrogen
Protons
Electrons
Neutrons
Nitrogen has seven electrons, seven protons and seven neutrons.
The Atom Oxygen
Protons
Electrons
Neutrons
Oxygen has eight electrons, eight protons and eight neutrons.
The Atom Fluorine
Protons
Electrons
Neutrons
Fluorine has nine electrons, nine protons and ten neutrons.
The Atom Neon
Protons
Neutrons
Neon has ten electrons, ten protons and ten neutrons.
Electrons
Isotopes
• Elements of the same element that have the same # of
protons & electrons BUT differing # of neutrons.
• Ex.
12
6C
13
6C
14
6C
# p+
#e-
#n0
12 C
6
6
6
238 U
92
92
92
32 P
15
15
15
12-6 =
6
238-92
= 146
32-15 =
17
Review
• Atomic # = # of protons- determines
the atom
• Atomic mass = # of protons + neutrons
• In neutral atoms: #protons = electrons
& many times neutrons
• To determine # of neutrons:
•
atomic weight - # of protons
Review
# protons- 6
# electrons-6
# of neutrons-6
Review
# protons- 80
# electrons-80
# of neutrons-120