Download The Modern Atomic Model

THE MODERN ATOMIC MODEL
• The Modern Model
• Nucleus contains protons and neutrons
• Cloudlike region surrounding nucleus
contains moving electrons.
PARTICLE CHARGES
• The number of protons equals the
number of electrons.
• Neutrons do not affect the charge of
the atom.
PARTICLE MASSES
• A Proton and a Neutron have about the same mass (1 amu).
• Electrons mass are around 2,000 times less than protons and neutrons.
• Protons and Neutrons contribute to most of the atom’s mass.
SCALE AND SIZE OF ATOMES
• Video
ATOMIC NUMBER
• Every atom of an element will always have the same number of protons
• Carbon will always have 6 protons, oxygen will always have 8 protons, and iron will
always have 26 protons.
• The atomic number identifies an element, and is unique to that element and
that element only!
• Periodic Table
ISOTOPES
• Even though atoms will always have the same number of protons, this does not
mean that they will always have the same number of neutrons.
• Isotopes are when atoms have the same number of protons but a different
number of neutrons.
MASS NUMBER
• To find the mass number of an isotope:
• (Protons+Neutrons)
• Most common isotope is Carbon-12
• (6 Protons+6Neutrons)
• All carbon atoms will react the same even if they have different mass
numbers.
• Board Examples