Atomic Structure Fundamentals

Atomic Structure

• Atomic Model:
  • Protons (positive charge) and Neutrons (no charge) reside in the nucleus.
  • Electrons (negative charge) orbit around the nucleus in energy levels or shells.
• Subatomic Particles:
  • Protons: positively charged, resides in nucleus, determines atomic number.
  • Neutrons: no charge, resides in nucleus, determines atomic mass.
  • Electrons: negatively charged, orbits nucleus, determines chemical properties.
• Energy Levels (Shells):
  • First shell (1s): 2 electrons
  • Second shell (2s and 2p): 8 electrons
  • Third shell (3s, 3p, and 3d): 18 electrons

Periodic Table

• Organized by:
  • Atomic number (number of protons)
  • Atomic mass (average mass of naturally occurring isotopes)
• Periods:
  • Horizontal rows, elements exhibit similar trends in chemical properties.
• Groups:
  • Vertical columns, elements exhibit similar chemical properties due to same number of valence electrons.
• Blocks:
  • s-block: first two columns, s-orbitals
  • p-block: last six columns, p-orbitals
  • d-block: middle ten columns, d-orbitals
  • f-block: bottom two rows, f-orbitals

Chemical Bonding

• Types of Bonds:
  • Ionic Bonds:
    • Formed between metals and nonmetals
    • Transfer of electrons, resulting in ions with opposite charges
  • Covalent Bonds:
    • Formed between nonmetals
    • Sharing of electrons, resulting in a molecular bond
  • Metallic Bonds:
    • Formed between metal atoms
    • Sea of delocalized electrons, binding atoms together
• Polarity:
  • Polar Covalent Bonds:
    • Unequal sharing of electrons, resulting in a partial positive and negative charge
  • Nonpolar Covalent Bonds:
    • Equal sharing of electrons, resulting in no net dipole moment

Metals and Nonmetals

• Metals:
  • Typically shiny, malleable, and good conductors of electricity
  • Often lose electrons to form ions (cations)
  • Found on the left side and center of the periodic table
• Nonmetals:
  • Typically dull, brittle, and poor conductors of electricity
  • Often gain electrons to form ions (anions)
  • Found on the right side of the periodic table
• Metalloids:
  • Exhibit intermediate properties between metals and nonmetals
  • Found on the border between metals and nonmetals in the periodic table

Atomic Structure

• Protons have a positive charge and reside in the nucleus, determining the atomic number.
• Neutrons have no charge and reside in the nucleus, determining the atomic mass.
• Electrons have a negative charge and orbit around the nucleus in energy levels or shells.

Subatomic Particles

• Protons: positively charged, resides in nucleus, determines atomic number.
• Neutrons: no charge, resides in nucleus, determines atomic mass.
• Electrons: negatively charged, orbits nucleus, determines chemical properties.

Energy Levels (Shells)

• First shell (1s): 2 electrons.
• Second shell (2s and 2p): 8 electrons.
• Third shell (3s, 3p, and 3d): 18 electrons.

Periodic Table

• Organized by atomic number (number of protons) and atomic mass (average mass of naturally occurring isotopes).
• Periods are horizontal rows, where elements exhibit similar trends in chemical properties.
• Groups are vertical columns, where elements exhibit similar chemical properties due to the same number of valence electrons.

Blocks

• s-block: first two columns, s-orbitals.
• p-block: last six columns, p-orbitals.
• d-block: middle ten columns, d-orbitals.
• f-block: bottom two rows, f-orbitals.

Chemical Bonding

• Ionic Bonds: formed between metals and nonmetals, involving the transfer of electrons, resulting in ions with opposite charges.
• Covalent Bonds: formed between nonmetals, involving the sharing of electrons, resulting in a molecular bond.
• Metallic Bonds: formed between metal atoms, involving a sea of delocalized electrons, binding atoms together.

Polarity

• Polar Covalent Bonds: unequal sharing of electrons, resulting in a partial positive and negative charge.
• Nonpolar Covalent Bonds: equal sharing of electrons, resulting in no net dipole moment.

Metals and Nonmetals

• Metals: typically shiny, malleable, and good conductors of electricity, often losing electrons to form ions (cations), found on the left side and center of the periodic table.
• Nonmetals: typically dull, brittle, and poor conductors of electricity, often gaining electrons to form ions (anions), found on the right side of the periodic table.
• Metalloids: exhibiting intermediate properties between metals and nonmetals, found on the border between metals and nonmetals in the periodic table.