How Atoms Differ Elements, Isotopes, and Ions

How Atoms Differ
Elements, Isotopes, and Ions
Slide Show
What makes atoms different?
• The number of protons in the nucleus.
• The Atomic Number indicates the number of
• An element is a pure substance made from
atoms that all have the same number of
• Examples: Gold, Copper, Mercury, and Sulfur
Examples of Elements
Can you guess the name?
Atoms & The Periodic Table
Atoms are arranged in order by their atomic #.
• These are atoms that contain
different number of neutrons!
• The atomic mass = # of protons +
# of neutrons.
• To find the number of neutrons,
simply subtract the number of
protons from the atomic mass.
Examples of Isotopes
Because most elements have more than one isotope, each element has an
average atomic mass.
Real Life Isotopes!
(Not actually carbon dating)
Ions involve electrons
• An atom is electrically neutral (meaning it has
the same number of protons and electrons.
• Sometimes, atoms gain or lost electrons.
• When this happens, an ion forms.
Positive vs. Negative Ions • When there
are more
electrons than
protons, it is a
negative ion!
• When there
are more
protons than
electrons, it is
a positive ion.
Let’s Practice – Ion or Isotope?
How to write symbols
Ions: How many Electrons? Isotopes – How many neutrons?
Ions have charges
Isotopes have different masses
(because neutrons vary)
F-1 or FU-238
K+1 or K+
Cl – 37
O – 18

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