Atomic Structure and Bonding

Atomic Structure and Bonding

• Atoms are the basic building blocks of matter, composed of a nucleus containing protons and neutrons, surrounded by electrons.
• Protons have a positive charge, neutrons are neutral, and electrons have a negative charge.
• The atomic number is the number of protons in an atom, and the mass number is the sum of protons and neutrons.
• Isotopes are atoms of the same element with different numbers of neutrons.
• Electrons occupy specific energy levels or shells around the nucleus, and each shell can hold a maximum number of electrons.
• Valence electrons are the electrons in the outermost shell and are involved in chemical bonding.
• Ionic bonds form when one atom loses electrons to become a positively charged ion, and another atom gains those electrons to become a negatively charged ion. These oppositely charged ions are then attracted to each other. The attraction forms an ionic bond.
• Covalent bonds form when atoms share electrons to achieve a more stable electron configuration. These shared electrons are attracted to the positively charged nuclei of both atoms.
• Metallic bonds are formed by the attraction between positively charged metal ions and mobile valence electrons. These delocalized electrons allow for the unique properties of metals, such as conductivity and malleability.
• The octet rule states that atoms tend to gain, lose, or share electrons to achieve a full outer electron shell of eight valence electrons (or two for hydrogen and helium).

Chemical Reactions

• Chemical reactions involve the rearrangement of atoms to form new substances.
• Reactants are the substances that undergo change, and products are the substances that are formed.
• Balancing chemical equations ensures that the number of atoms of each element is the same on both sides of the equation.
• Chemical reactions are classified based on various characteristics including:
  • Decomposition: A single substance breaks down into two or more simpler substances.
  • Combination: Two or more substances combine to form a single substance.
  • Single replacement: One element replaces another element in a compound.
  • Double replacement: The positive ion of one compound replaces the positive ion of another compound.
• The rate of a chemical reaction is affected by factors such as temperature, concentration of reactants, surface area, and catalysts.
• Exothermic reactions release energy to the surroundings, while endothermic reactions absorb energy from the surroundings.

States of Matter

• Matter exists in three primary states: solid, liquid, and gas.
• Solids have a fixed shape and volume due to strong intermolecular forces holding the particles in fixed positions.
• Liquids have a definite volume but take the shape of their container. Intermolecular forces are weaker than in solids, allowing particles to move past each other.
• Gases have neither a definite shape nor a definite volume and expand to fill their container. Intermolecular forces are very weak, and particles move freely.

Periodic Table

• The periodic table arranges elements in order of increasing atomic number and according to similarities in properties.
• Elements are grouped into families or periods based on their electronic configuration and properties.
• Metals, nonmetals, and metalloids are general classifications based on their properties.
  • Metals are typically good conductors of heat and electricity, shiny, ductile, and malleable.
  • Nonmetals are typically poor conductors of heat and electricity, and many are gases or brittle solids at room temperature.
  • Metalloids have properties that are intermediate between those of metals and nonmetals.
• Trends in properties such as atomic radius, ionization energy, and electronegativity are observed across periods and groups.

Solutions

• Solutions are homogeneous mixtures of two or more substances.
• The solvent is the substance present in the largest amount, and the solute is the substance dissolved in the solvent.
• The concentration of a solution describes the amount of solute present in a given amount of solvent or solution.
• Various methods exist for expressing concentration, such as molarity, molality, and percentage concentration.
• Solubility describes the maximum amount of a solute that can dissolve in a given amount of solvent at a specific temperature and pressure.
• Factors affecting solubility include temperature and the nature of the solute and solvent.

Explore the fundamentals of atomic structure and the different types of chemical bonds. This quiz covers topics like atomic numbers, isotopes, valence electrons, and the distinctions between ionic and covalent bonds. Test your understanding of how atoms interact and form compounds.