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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 protons. An element is a pure substance made from atoms that all have the same number of protons.
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How Atoms DifferElements, Isotopes, and Ions Slide Show
What makes atoms different? • The number of protons in the nucleus. • The Atomic Number indicates the number of protons. • An element is a pure substance made from atoms that all have the same number of protons. • Examples: Gold, Copper, Mercury, and Sulfur
Atoms & The Periodic Table Atoms are arranged in order by their atomic #.
Isotopes • 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 IsotopesBecause most elements have more than one isotope, each element has an average atomic mass.
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.
How to write symbols Ions: How many Electrons? Ions have charges Ca+2 F-1 or F- K+1 or K+ Al+3 O-2 Isotopes – How many neutrons? Isotopes have different masses (because neutrons vary) C-14 U-238 H-3 Cl – 37 O – 18