Atoms, Ions, Molecules
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Identify types of substances: Atom, Ion, Molecule
Substances shown:
H
Mg
Mg
H
H
H
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Definition of Atom
Tiny indivisible particle of an element
Each element has one kind of atom
118 known chemical elements
Atoms are neutral
Examples:
Oxygen (O)
Hydrogen (H)
Sodium (Na)
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Atomic Structure
Composed of:
Neutrons
Electrons
Nucleus (contains Protons)
Electrons are found in electron clouds or orbitals
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Carbon Atom Structure
Protons (p+) = 6
Electrons (e) = 6
Neutrons (n°) = 6
Atomic Mass: 12.0107
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Oxygen Atom Structure
Protons (p+) = 8
Electrons (e) = 8
Neutrons (n°) = 8
Atomic Mass: 15.9994
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Atom Notation
Notation format: XA
Z: Atomic Number = number of protons
Mass Number = number of protons + neutrons
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Hydrogen Atom Notation
Notation: H1
Atomic Number = 1
Mass Number = 1
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Example of Elements with Protons, Electrons & Neutrons
Element:
Element: 11 Proton: 11 Neutron: 12
Element: 17 Proton: 17 Neutron: 18
Element: 7 Proton: 7 Neutron: 7
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Summary Table
Symbol | Atomic # | Atomic Mass | Proton | Electron | Neutron
C | 6 | 12 | 6 | 6 | 6
K | 19 | 39 | 19 | 19 | 20
Cu | 29 | 64 | 29 | 29 | 35
Sn | 50 | 119 | 50 | 50 | 69
Au | 79 | 197 | 79 | 79 | 118
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Isotopes
Definition: Atoms with the same atomic number but different mass numbers
Examples:
Protium (1H)
Deuterium (2H)
Tritium (3H)
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Uses of Isotopes
Uranium-235
Used as fuel for nuclear reactors
Uranium-238
Determining age of marine sediments
Carbon-14
Carbon dating for archaeological materials
Iodine-131
Treatment for thyroid cancer
Technetium-99
Imaging for diagnostics
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Additional Uses of Isotopes
Cobalt-60
Radiation for cancer treatment
Thallium-201
Assessment for heart tissue damage
Americium-241
Thickness measurement in steel and paper
Californium-252
Moisture content measurement in construction
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Atoms combine to form Molecules or Ions
Electrons may be lost or gained
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Ion Formation
Loss of electrons: Cation
Gain of electrons: Anion
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Definition of Ion
Formed when an atom loses or gains electrons
Types:
Monoatomic (e.g., N3-, Ba2+)
Polyatomic (e.g., CO3 2-)
Positive ions (cations) or negative ions (anions)
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Classification of Elements: Metals, Nonmetals, and Metalloids
Examples of Metals:
Na, Mg, Al
Examples of Nonmetals:
C, O, N
Metalloids: Boron (B), Silicon (Si), etc.
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Naming Monoatomic Ions
Examples:
Group 1A: Na+ (Sodium ion)
Group 2A: Mg2+ (Magnesium ion)
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Transition Metals
Vary in number of electrons lost
Naming Methods: Classical & Stock
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Classical Naming Method
Suffixes:
-ous = lower charge (e.g., Fe2+ = Ferrous)
-ic = higher charge (e.g., Fe3+ = Ferric)
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Examples of Classical vs. Stock Method
Cu+ = Cuprous ion
Cu2+ = Cupric ion
Sn2+ = Stannous ion
Sn4+ = Stannic ion
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Stock Naming Method
Roman numeral indicates charge in parentheses
Example: Fe2+ = Ferrous iron (II)
Example: Fe3+ = Ferric iron (III)
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Examples of Naming Ions in Stock Method
Cu+ = Copper (I)
Cu2+ = Copper (II)
Sn2+ = Tin (II)
Sn4+ = Tin (IV)
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Naming Monoatomic Anions
Examples:
S2- = Sulfide ion
Br- = Bromide ion
F- = Fluoride ion
O2- = Oxide ion
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Naming Polyatomic Anions
Examples:
OH- = Hydroxide ion
CN- = Cyanide ion
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Naming Polyatomic Anions with Oxygen
Examples:
NO2- = Nitrite ion
NO3- = Nitrate ion
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Naming Anions with Sulfur Substitution
Examples:
OCN- = Cyanate ion
SCN- = Thiocyanate ion
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Definition of Molecule
Formed by nonmetals sharing electrons
Diatomic or Polyatomic
Examples:
H2O, H2S, C6H12O6, C10H8
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Diatomic Molecules
Nonmetallic elements that exist as diatomic molecules
Examples:
N2, O2, H2, F2, Cl2
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Molecular Compounds
Composed of different elements, can be diatomic or polyatomic
Examples:
HCl, HBr, H2S, H2O, CO2
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Naming Molecular Compounds
Use Greek prefixes for both elements
Add suffix -ide to the second element
Example: SF6 = Sulfur hexafluoride
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Greek Prefixes for Naming:
1 = mono-
2 = di-
3 = tri-
4 = tetra-
5 = penta-
6 = hexa-
7 = hepta-
8 = octa-
9 = nona-
10 = deca-
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Naming Examples
P2S3 = Diphosphorus trisulfide
CF3 = Carbon trifluoride
P2O5 = Diphosphorus pentaoxide
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Summary on Ion Naming
Monoatomic Ion (Cation):
Unchanged name for groups 1A and 2A
Transition metals: Classical or Stock naming
Monoatomic Ion (Anion):
Root name + suffix -ide
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Summary on Polyatomic and Molecular Compounds
Polyatomic Ion: Atomic constituent + suffix –ide
Polyatomic Ion with Oxygen:
Root name + -ite (lesser)
Root name + -ate (greater)
Molecular Compounds: Greek prefixes + -ide suffix