Chemistry Ionic Bonds and Electron Subshells

Electron Subshells

• An s subshell can hold 2 electrons.
• A p subshell can hold 6 electrons.
• A d subshell can hold 10 electrons.

Energy Levels and Subshells

• The first energy level has only an s subshell.
• The second energy level has s and p subshells.
• The third energy level has s, p, and d subshells.

Hund's Rule

• Electrons fill orbitals singly before pairing up.

Exceptions to Subshell Filling Order

• Copper and chromium do not follow the usual order of filling the 4s subshell before 3d.

Ionic Bonds

• Ionic bonds form through the electrostatic attraction between oppositely charged ions.
• Group 1 ions have a +1 charge.
• Group 2 ions have a +2 charge.
• Group 6 ions have a -2 charge.
• Group 7 ions have a -1 charge.
• Sodium loses an electron to become Na⁺; Chlorine gains an electron to become Cl⁻; these ions attract to form NaCl.

Properties of Ionic Compounds

• Conduct electricity when molten or dissolved in water.
• Have high melting and boiling points.
• Often soluble in water.

Factors Affecting Ionic Bond Strength

• Ion size.
• Ion charge.

Covalent Bonds

• Covalent bonds involve a shared pair of electrons.

Metallic Bonds

• Transition metals do not fill 4s before 3d.
• Strong attraction between positive ions and delocalized electrons.
• Factors affecting strength:
  • Size of metal ion.
  • Charge on metal ion.

Properties of Metals

• Conduct heat and electricity.
• Ductile (can be drawn into wires).
• Malleable (can be hammered into sheets).

Intermolecular Forces

• Three types of intermolecular forces:
  • Hydrogen bonds.
  • Permanent dipole-dipole forces.
  • Van der Waals forces.
• Strength order: Hydrogen bonds > Permanent dipole-dipole > Van der Waals.
• Van der Waals forces exist in non-polar molecules.
• Permanent dipole-dipole forces occur in polar molecules.
• Hydrogen bonds require hydrogen with nitrogen, oxygen, or fluorine.

Chemical Reactions

• Displacement reactions occur when a more reactive element replaces a less reactive element in a compound.

Calculations

• Moles = mass/molar mass
• Avogadro's constant (6.02 x 10²³) represents the number of particles in a mole.
• Relative atomic mass: average mass of an atom of an element relative to 1/12 C-12.
• Relative molecular mass: average mass of a molecule relative to 1/12 C-12.
• % yield = (actual yield/theoretical yield) x 100

Periodic Table

• The periodic table is organized into groups (vertical columns) and periods (horizontal rows).
• S block: groups 1 and 2.
• D block: transition metals.
• P block: groups 3 to 7.

Periodic Trends

• Atomic radius increases down a group.
• First ionization energy decreases down a group.
• Melting points decrease down groups 1 and 2.
• Electronegativity decreases down group 7.
• Atomic radius decreases across a period.
• Electronegativity increases across a period.
• Melting points generally increase across a period, then decrease, due to the trends in bonding strengths.

Exceptions to Trends

• Group 3 elements have lower first ionization energy than group 2 elements because the electron is removed from a p subshell.
• Group 6 elements have lower first ionization energy than group 5 elements due to electron repulsion.

Oxidation/Reduction

• Oxidation: loss of electrons.
• Reduction: gain of electrons.
• Reducing agent: loses electrons.
• Oxidizing agent: gains electrons.

Oxidation States

• Group 1 metals usually have an oxidation state of +1.
• Group 2 metals usually have an oxidation state of +2.
• Group 6 elements commonly have an oxidation state of -2.
• Group 7 elements commonly have an oxidation state of -1.

Cell Structure and Function

• Cytoplasm: site of chemical reactions.
• Vesicles: transport materials.
• Nucleolus: produces ribosomes and RNA.
• Cell wall: provides rigidity and protection,
• Chloroplasts: site of photosynthesis
• Plasmodesmata: channels through cell wall for transport between cells
• Amyoplasts: store and convert starch
• Vacuole: stores water and chemicals, maintains turgor.
• Tonoplast: membrane surrounding vacuole; protects and controls water flow.
• Gram-positive bacteria have a more permeable cell wall than gram-negative bacteria.
• Palisade cells are tightly packed with chloroplasts and a large vacuole.

This quiz covers key concepts related to electron subshells and ionic bonds. It explains the capacity of different subshells, Hund's Rule, and exceptions to subshell filling orders. Additionally, it discusses the properties of ionic compounds and the behavior of charged ions.