Basic Chemistry 1 Chapter 02 1 Chapter 2 Basic Chemistry Vital Force - Vitality 2 • Organisms composed primarily (96%) of only four elements – Carbon, Oxygen, Hydrogen, Nitrogen – COHN 3 Atomic Structure Atoms – Smallest units of elements Consist of 3 subatomic particles Protons (+) Neutrons (no charge) Electrons (-)
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Chapter 2 Basic Chemistry Nixon - Lane Library · Atomic Structure Atoms – Smallest units of elements Consist of 3 subatomic particles Protons (+) Neutrons (no charge) Electrons
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Basic Chemistry
1Chapter 02
1
Chapter 2
Basic Chemistry
Vital Force - Vitality
2
• Organisms composed primarily (96%) of only four elements
– Carbon, Oxygen, Hydrogen, Nitrogen
– COHN
3
Atomic StructureAtoms – Smallest units of elementsConsist of 3 subatomic particles
Protons (+)Neutrons (no charge)Electrons (-)
Basic Chemistry
2Chapter 02
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• Each element represented by unique
atomic symbol
– One or two letters
– First letter capitalized
– Atomic #
– Mass #
• Unit of measure is a Dalton
Atomic Symbols
MassMassNumberNumber
AtomicAtomicNumberNumber
AtomicAtomicSymbolSymbol
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Carbon
C
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• Isotopes:
– Atoms of the same element with a differing numbers of neutrons
– Still has same # of protons
Isotopes
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Radioisotopes
– Some isotopes spontaneously decay
• Unstable nucleus
• Radioactive decay transforms one element into another (i.e. Carbon-14 into Nitrogen-14)
• Give off energy in the form of rays and subatomic particles
• Dating
– Half life of C-14 (5.7k years)
• Can be used as tracers (Iodine*)
• Mutagenic – Can cause cancer
Basic Chemistry
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Some Medical Uses forLow Level Radiation
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Electrons
• In neutral atoms p = e- (+ balances -)• Electrons are attracted to the positive nucleus
– Revolve around nucleus in orbitals
• Energy Levels (aka: electron shells) “Bohr Model”– concentric circles around the nucleus– 1st Shell: 2 e-– Subsequent Shells: 8 e-
• (Octet Rule)• Goal = have full outer shell Reactive?? Why
– Hydrogen: 1 shell, goal = 2 e-– All other atoms, goal = 8 e-
• How can an atom be neutral but unstable?• So how do I become stable? Hmmmm
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Bohr Models of Atoms
Basic Chemistry
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Organization of Periodic Table • Elements grouped in periodic table based