Atomic Structure Fundamentals

Atomic Structure

• Atomic Models:
  • Rutherford's Atomic Model: Atom consists of a nucleus (protons and neutrons) and electrons orbiting around it.
  • Bohr's Atomic Model: Electrons occupy specific energy levels (shells) around the nucleus.
• Subatomic Particles:
  • Protons: Positive charge, present in the nucleus.
  • Neutrons: No charge, present in the nucleus.
  • Electrons: Negative charge, orbit around the nucleus.
• Atomic Number (Z): Number of protons in an atom's nucleus, unique to each element.
• Mass Number (A): Sum of protons and neutrons in an atom's nucleus.

Periodic Classification of Elements

• Mendeleev's Periodic Table: Arrangement of elements in a tabular form based on their atomic masses and chemical properties.
• Periods: Horizontal rows in the periodic table, representing elements with similar electronic configurations.
• Groups: Vertical columns in the periodic table, representing elements with similar chemical properties.
• Families of Elements:
  • Alkali Metals (Group 1): Highly reactive, lose one electron to form a cation.
  • Alkaline Earth Metals (Group 2): Less reactive, lose two electrons to form a cation.
  • Halogens (Group 17): Highly reactive, gain one electron to form an anion.
  • Noble Gases (Group 18): Unreactive, full outermost energy level.

Chemical Bonding

• Types of Chemical Bonds:
  • Ionic Bond: Formation of ions with opposite charges, resulting in a strong electrostatic attraction.
  • Covalent Bond: Sharing of electrons between atoms, resulting in a strong chemical bond.
• Electronegativity: The ability of an atom to attract electrons in a covalent bond.
• Polarity of Molecules: The uneven distribution of electrons in a covalent bond, resulting in a partial positive and negative charge.

Stoichiometry

• Mole Concept: A unit of measurement in chemistry, representing 6.022 x 10^23 particles (atoms, molecules, or ions).
• Molar Mass: The mass of one mole of a substance, expressed in grams per mole (g/mol).
• Empirical and Molecular Formula: Representation of a compound's composition, with empirical formula showing the simplest whole-number ratio of atoms and molecular formula showing the actual number of atoms.

States of Matter

• Solid: Particles are closely packed, with a fixed shape and volume.
• Liquid: Particles have some freedom of movement, with a fixed volume but variable shape.
• Gas: Particles have complete freedom of movement, with neither a fixed shape nor volume.
• Phase Changes: Changes between states of matter, such as melting, boiling, and condensation.

Atomic Structure

• Atom consists of a nucleus (protons and neutrons) and electrons orbiting around it.
• Rutherford's Atomic Model reveals the nucleus and electron orbitals.
• Bohr's Atomic Model explains electrons occupying specific energy levels (shells) around the nucleus.
• Protons have a positive charge and are present in the nucleus.
• Neutrons have no charge and are present in the nucleus.
• Electrons have a negative charge and orbit around the nucleus.

Atomic Number and Mass Number

• Atomic Number (Z) is the number of protons in an atom's nucleus, unique to each element.
• Mass Number (A) is the sum of protons and neutrons in an atom's nucleus.

Periodic Classification of Elements

• Mendeleev's Periodic Table arranges elements in a tabular form based on atomic masses and chemical properties.
• Periods are horizontal rows in the periodic table, representing elements with similar electronic configurations.
• Groups are vertical columns in the periodic table, representing elements with similar chemical properties.
• Alkali Metals (Group 1) are highly reactive, losing one electron to form a cation.
• Alkaline Earth Metals (Group 2) are less reactive, losing two electrons to form a cation.
• Halogens (Group 17) are highly reactive, gaining one electron to form an anion.
• Noble Gases (Group 18) are unreactive, having a full outermost energy level.

Chemical Bonding

• Ionic Bonds form when ions with opposite charges attract each other, resulting in a strong electrostatic attraction.
• Covalent Bonds form when atoms share electrons, resulting in a strong chemical bond.
• Electronegativity is the ability of an atom to attract electrons in a covalent bond.
• Polarity of Molecules occurs when electrons are unevenly distributed in a covalent bond, resulting in a partial positive and negative charge.

Stoichiometry

• A mole is a unit of measurement in chemistry, representing 6.022 x 10^23 particles (atoms, molecules, or ions).
• Molar Mass is the mass of one mole of a substance, expressed in grams per mole (g/mol).
• Empirical and Molecular Formula represent a compound's composition, with empirical formula showing the simplest whole-number ratio of atoms and molecular formula showing the actual number of atoms.

States of Matter

• Solids have particles that are closely packed, with a fixed shape and volume.
• Liquids have particles with some freedom of movement, with a fixed volume but variable shape.
• Gases have particles with complete freedom of movement, with neither a fixed shape nor volume.
• Phase Changes occur when substances change between states of matter, such as melting, boiling, and condensation.

Learn about atomic models, subatomic particles, and atomic number. Understand Rutherford's and Bohr's atomic models, protons, neutrons, and electrons.