Comprehensive Study Notes: Types of Chemical Bonds and Nomenclature

Curricular Framework, Competencies, and Educational Context

• Academic Institution and Department:

  • Universidad de Monterrey (UDEM), Vicerrectoría de Educación Media Superior, Prepa UDEM.

  • Academia de Ciencias Naturales / Academy of Natural Science.

  • Affiliation: International Baccalaureate (IB) World School (Colegio del Mundo / École du Monde).

  • Course: Introduction to Experimental Sciences (CLU: Introduction to Experimental Sciences).

  • Unit and Task: Topic $1.5$ Types of Chemical Bonds / Actividad 7: Types of bonds.

  • Student Identifier: Arcelia Treviño Fernández, ID: $689145$, Group / Room: $9741$, Evaluation Date: $12/10/2026$.

• International Baccalaureate (IB) Profile Attributes:

  • Inquirers: Curiosity is nurtured, actively developing skills for inquiry and research. Learning occurs both independently and collaboratively, maintained with enthusiasm and a sustained love of learning throughout life.

• Competencies and Learning Attributes:

  • Basic Disciplinary Competence:

  • CE-$2$: Fundaments opinions about the impact of science and technology on daily life, assuming ethical considerations.

  • Future Competencies:

  • Competency $12$ (Attributes of Creative and Innovative Thinking):

    • Attribute $12.6$: Creates or uses models and simulations to explore different future scenarios. Uses modeling and simulation software to visualize how different variables could impact the future in areas such as economics, climate change, or health.

  • Competency $13$ (Attributes of Ethical Thinking):

    • Attribute $13.2$: Considers the possible consequences of decisions and actions on oneself, others, and society.

• Academic Integrity Policy:

  • Academic submissions require strict adherence to the institutional honor code, certifying that any text, concept, or reference not originating from student authorship is cited, including sources derived from artificial intelligence tools.

  • Any academic dishonesty is evaluated with a grade of zero ($0$), followed by protocols overseen by the Academic Integrity Committee of Prepa UDEM.

• Evaluation Rubric Criteria (Actividad 7: Types of Bonds):

  • The formal assessment consists of $10$ discrete evaluation criteria, scored across Satisfactory ($2$ points), Partially Satisfactory ($1$ point), and No points ($0$ points), for a total possible score of $20$ points:

  • Criterion $1$: Correctly identifies between metals and non-metals from different compounds.

  • Criterion $2$: Correctly identifies the bonds as ionic and covalent compounds.

  • Criterion $3$: Correctly draws the Lewis electron dot structure for different elements.

  • Criterion $4$: Correctly identifies the periodic table group they belong to.

  • Criterion $5$: Correctly identifies the type of element as metal or nonmetal.

  • Criterion $6$: Correctly identifies the elements that form positive ions and negative ions.

  • Criterion $7$: Correctly draws the Lewis electron dot structure for different compounds.

  • Criterion $8$: Correctly identifies the type of bond that joins them (covalent or ionic).

  • Criterion $9$: Correctly compares ionic and covalent bonds.

  • Criterion $10$: Correctly contrasts ionic and covalent bonds.

Fundamentals of Chemical Bonding and Atomic Stability

• Core Learning Objectives:

  • Objective $1.5.1$: Predict the positive ions (cations) that form when metals lose valence electrons.

  • Objective $1.5.2$: Predict the negative ions (anions) that form when nonmetals gain electrons.

  • Objective $1.5.3$: Compare and contrast between ionic and covalent compounds (bonds).

  • Objective $1.5.4$: State how compounds are formed and how they are named applying ionic charges.

• Definition of a Chemical Bond:

  • A chemical bond represents the attractive forces that hold atoms together in molecules or formula units.

  • Mechanism of Attraction: Electrons experience a simultaneous electrostatic force of attraction from the nuclei of both participating atoms.

  • This negative-positive-negative electrostatic attraction holds the two participating particles together.

  • A single chemical bond is constituted by one shared pair of electrons ($2$ electrons).

• The Octet Rule:

  • The Octet Rule is the tendency of an atom to gain, lose, or share electrons in order to achieve a complete outer valence shell consisting of $8$ valence electrons (occupying the highest energy level), thereby achieving thermodynamic stability.

  • Exception to the Octet Rule: Helium ($He$) reaches complete thermodynamic stability with only $2$ valence electrons (satisfying the duet rule).

• Noble Gas Configuration and Inherent Stability:

  • Elements of Group $\text{VIII A}$ (also classified as Group $18$, the Noble Gases) possess a naturally complete valence electron shell.

  • Because their outer shells are filled, noble gases represent the only inherently stable elements in their standard elemental states, and therefore they do not combine spontaneously with other elements.

  • Noble Gas Group $\text{VIII A}$ elements and atomic data:

  • Helium ($He$): Atomic number $2$, standard atomic mass $4.00\,g/mol$, complete shell of $2$ electrons.

  • Neon ($Ne$): Atomic number $10$, standard atomic mass $20.18\,g/mol$, stable valence shell of $8$ electrons.

  • Argon ($Ar$): Atomic number $18$, standard atomic mass $39.95\,g/mol$, stable valence shell of $8$ electrons.

  • Krypton ($Kr$): Atomic number $36$, standard atomic mass $83.80\,g/mol$, stable valence shell of $8$ electrons.

  • Xenon ($Xe$): Atomic number $54$, standard atomic mass $131.29\,g/mol$, stable valence shell of $8$ electrons.

  • Radon ($Rn$): Atomic number $86$, mass number $(222)\,g/mol$, stable valence shell of $8$ electrons.

Formation, Characteristics, and Classification of Ions

• Definition of an Ion:

  • An ion is defined as an atom or group of atoms that has undergone a net change in its electrostatic charge by either losing or gaining one or more electrons.

  • When a neutral atom loses one or more electrons, the balance between protons and electrons is disrupted, resulting in a net positive charge.

  • When a neutral atom gains one or more electrons, the surplus of negative particles produces a net negative charge.

• Cations (Positive Ions):

  • A cation is an ion that has lost one or more electrons, producing a net positive charge.

  • Formation: Cations form when metallic elements lose their valence electrons due to their relatively low electronegativity values.

  • Examples of monoatomic cations: Potassium ($K^+$), Sodium ($Na^+$).

  • Example of polyatomic cation: Ammonium ($NH_4^+$ or $NH_4^{+1}$).

  • Formation mechanism of Sodium ($Na$):

  • A neutral sodium atom ($Na$) with electron configuration $2, 8, 1$ loses its single outer valence electron.

  • Result: A sodium cation ($Na^+$) possessing an electron configuration of $2, 8$, achieving an octet identical to Neon.

• Anions (Negative Ions):

  • An anion is an ion that has gained one or more electrons, producing a net negative charge.

  • Formation: Anions form when nonmetallic elements gain electrons due to their high electronegativity values.

  • Examples of monoatomic anions: Sulfide ($S^{-2}$), Chloride ($Cl^-$), Fluoride ($F^-$).

  • Example of polyatomic anion: Sulfate ($SO_4^{-2}$).

  • Formation mechanism of Fluorine ($F$):

  • A neutral fluorine atom ($F$) with electron configuration $2, 7$ gains $1$ electron.

  • Result: A fluoride anion ($F^-$) designated as $[2, 8]^-$ to reflect a completed valence shell.

• Structural Classification of Ions:

  • Monoatomic Ions: Consist of a single atomic element bearing an electrical charge.

  • Examples: $Na^{+1}$, $Cl^-$.

  • Polyatomic Ions: Consist of a stable, covalently bonded group of two or more distinct elements that collectively carry an overall net electrical charge.

  • Examples: Sulfate ($SO_4^{-2}$), Ammonium ($NH_4^{+1}$), Phosphate ($PO_4^{-3}$), Sulfite ($SO_3^{-2}$).

• Cation Valences Reference:

  • Cations with $+1$ Valence Charge:

  • Hydrogen: $H^{+1}$

  • Lithium: $Li^{+1}$

  • Sodium: $Na^{+1}$

  • Potassium: $K^{+1}$

  • Rubidium: $Rb^{+1}$

  • Cesium: $Cs^{+1}$

  • Francium: $Fr^{+1}$

  • Silver: $Ag^{+1}$

  • Ammonium: $NH_4^{+1}$

  • Cations with $+2$ Valence Charge:

  • Beryllium: $Be^{+2}$

  • Magnesium: $Mg^{+2}$

  • Calcium: $Ca^{+2}$

  • Strontium: $Sr^{+2}$

  • Barium: $Ba^{+2}$

  • Radium: $Ra^{+2}$

  • Zinc: $Zn^{+2}$

  • Cadmium: $Cd^{+2}$

  • Cations with $+3$ Valence Charge:

  • Aluminum: $Al^{+3}$

  • Boron: $B^{+3}$

Comparative Analysis of Ionic and Covalent Bonds

• Taxonomy of Chemical Bonding:

  • Chemical bonds are classified fundamentally into ionic and covalent bonds based on the participating elements and electron interaction behavior.

• Mechanisms of Bond Types:

  • Ionic Bonds:

  • Electrostatic attraction forces generated between oppositely charged ions.

  • Involve the outright transfer of valence electrons from one atom to another.

  • Occur typically between a Metal (low electronegativity electron donor) and a Nonmetal (high electronegativity electron acceptor).

  • When an ionic bond forms, the metallic species becomes a positive cation ($+$) and the nonmetallic species becomes a negative anion ($-$).

  • Covalent Bonds:

  • Involve the direct sharing of valence electrons between atoms.

  • Atoms engaged in covalent bonds do not form independent ions; bonding is maintained exclusively by electron pair sharing.

  • Occur typically between two or more Nonmetal elements.

  • A molecule is formed when two or more atoms bond covalently.

  • Metallic Bonds (Comparative Reference):

  • Characterized by delocalized valence electrons pooled across a metallic lattice.

• Covalent Bonding Mechanisms in Carbon and Hydrogen:

  • Carbon ($C$) is a nonmetal located in Group $14$ ($\text{IV A}$) with $4$ valence electrons. It requires $4$ additional electrons to complete an octet.

  • Hydrogen ($H$) is a nonmetal with $1$ valence electron in its $1s$ orbital, requiring $1$ additional electron to attain the stable helium duet configuration.

  • By sharing electrons, one Carbon atom can bond with four Hydrogen atoms to form methane ($CH_4$), allowing all five participating atoms to achieve closed-shell electron stability.

  • In water ($H_2O$), an Oxygen atom shares two pairs of electrons with two separate Hydrogen atoms, satisfying both duets for Hydrogen and an octet for Oxygen.

• Direct Comparison (Similarities) Between Ionic and Covalent Bonds:

  • Both represent chemical bonding interactions that join elemental atoms together.

  • Both drive the synthesis of distinct chemical compounds with properties different from their constituent elements.

  • Both mechanisms operate utilizing valence electrons situated in the outermost energy levels.

  • Both bonding pathways are directed toward acquiring $8$ valence electrons to satisfy the Octet Rule and achieve thermodynamic stability (with duet exceptions such as Hydrogen).

• Direct Contrast (Differences) Between Ionic and Covalent Compounds:

  • Electron Distribution:

  • Ionic: Involves the complete transfer of electrons from metal to nonmetal.

  • Covalent: Involves the mutual sharing of valence electrons between nonmetals.

  • Elemental Composition:

  • Ionic: Consists of a Metal bonded to a Nonmetal.

  • Covalent: Consists exclusively of Nonmetal atoms bonded to Nonmetal atoms.

  • Structural and Representative Units:

  • Ionic: Forms extended crystal lattices composed of alternating cations and anions (represented by formula units).

  • Covalent: Forms discrete, independent molecules.

  • Melting and Boiling Points:

  • Ionic: Characterized by high melting points ($\text{mp}$) and high boiling points ($\text{bp}$) due to robust omnidirectional electrostatic forces in the lattice.

  • Covalent: Characterized by molecular structures exhibiting relatively low melting and boiling points.

  • Physical State at Room Temperature ($25\,^{\circ}\text{C}$):

  • Ionic: Exists as crystalline solids at room temperature.

  • Covalent: Typically exists as liquids or gases at room temperature (though solid molecular compounds exist).

  • Electrical Conductivity:

  • Ionic: Excellent conductors of electricity when melted (liquid state) or dissolved in aqueous solutions, because the crystal lattice dissociates into mobile charge-carrying ions. Non-conductive in rigid solid state.

  • Covalent: Non-conductors of electricity in all phases due to the absence of free mobile ions or delocalized electrons.

  • Representative Examples:

  • Ionic Compounds: Sodium chloride ($NaCl$), Magnesium iodide ($MgI_2$), Aluminum chloride ($AlCl_3$).

  • Covalent Compounds: Carbon dioxide ($CO_2$), Dichlorine ($Cl_2$), Carbon tetrachloride ($CCl_4$), Water ($H_2O$), Methane ($CH_4$), Trichlorofluoromethane ($CFCl_3$).

Lewis Electron Dot Structures and Empirical Compound Analysis

• Elemental Group Identification and Classification:

  • Sodium ($Na$):

  • Periodic Table Group: Group $1$

  • Elemental Type: Metal

  • Valence Electron Count: $1$

  • Lewis Electron Dot Structure: Symbol $\text{Na}$ with a single dot placed on the top.

  • Bromine ($Br$):

  • Periodic Table Group: Group $17$

  • Elemental Type: Nonmetal

  • Valence Electron Count: $7$

  • Lewis Electron Dot Structure: Symbol $\text{Br}$ with two pairs on top and bottom, one pair on the right, and one single dot on the left.

  • Nitrogen ($N$):

  • Periodic Table Group: Group $15$

  • Elemental Type: Nonmetal

  • Valence Electron Count: $5$

  • Lewis Electron Dot Structure: Symbol $\text{N}$ with one electron pair on top, and single unpaired dots on the left, right, and bottom.

• Ion Formation Predictions in Compounds:

  • Aluminum ($Al$) and Chlorine ($Cl$) in Aluminum Chloride ($AlCl_3$):

  • Aluminum ($Al$): Metal that acts as a cation ($Al^{+3}$, positive ion) by losing its $3$ valence electrons.

  • Chlorine ($Cl$): Nonmetal that acts as an anion ($Cl^-$, negative ion) by gaining $1$ electron per atom to complete its octet.

  • Calcium ($Ca$) and Fluorine ($F$) in Calcium Fluoride ($CaF_2$):

  • Calcium ($Ca$): Metal that acts as a cation ($Ca^{+2}$, positive ion) by losing its $2$ valence electrons.

  • Fluorine ($F$): Nonmetal that acts as an anion ($F^-$, negative ion) by gaining $1$ electron per atom to complete its octet.

• Compound Bond Classification Analysis:

  • Aluminum Chloride ($AlCl_3$):

  • Constituent Elements: Aluminum ($Al$, Metal) and Chlorine ($Cl$, Nonmetal).

  • Bond Type: Ionic bond.

  • Carbon Tetrachloride ($CCl_4$):

  • Constituent Elements: Carbon ($C$, Nonmetal) and Chlorine ($Cl$, Nonmetal).

  • Bond Type: Covalent bond.

  • Sodium Chloride ($NaCl$):

  • Constituent Elements: Sodium ($Na$, Metal) and Chlorine ($Cl$, Nonmetal).

  • Bond Type: Ionic bond.

  • Water ($H_2O$):

  • Constituent Elements: Hydrogen ($H$, Nonmetal) and Oxygen ($O$, Nonmetal).

  • Bond Type: Covalent bond.

  • Magnesium Iodide ($MgI_2$):

  • Constituent Elements: Magnesium ($Mg$, Metal) and Iodine ($I$, Nonmetal).

  • Bond Type: Ionic bond.

  • Methane ($CH_4$):

  • Constituent Elements: Carbon ($C$, Nonmetal) and Hydrogen ($H$, Nonmetal).

  • Bond Type: Covalent bond.

  • Carbon Dioxide ($CO_2$):

  • Constituent Elements: Carbon ($C$, Nonmetal) and Oxygen ($O$, Nonmetal).

  • Bond Type: Covalent bond.

  • Trichlorofluoromethane ($CFCl_3$):

  • Constituent Elements: Carbon ($C$, Nonmetal), Fluorine ($F$, Nonmetal), Chlorine ($Cl$, Nonmetal).

  • Bond Type: Covalent bond.

• Graphical Lewis Structures of Selected Compounds:

  • Water ($H_2O$):

  • Covalently bonded molecule.

  • Central Oxygen atom bonded to two Hydrogen atoms via single covalent bonds (shared electron pairs), leaving two non-bonding lone pairs ($4$ non-bonding electrons) on Oxygen.

  • Magnesium Iodide ($MgI_2$):

  • Ionically bonded formula unit.

  • Central Magnesium atom transfers $2$ valence electrons (one to each flanking Iodine atom).

  • Represented with Magnesium between two Iodine atoms, each Iodine completing an octet of $8$ electrons.

• Methane ($CH_4$):

  • Covalently bonded molecule.

  • Central Carbon atom shares its $4$ valence electrons symmetrically with four surrounding Hydrogen atoms, producing four shared electron pairs ($C:H$ bonds).

• Aluminum Chloride ($AlCl_3$):

  • Ionically bonded compound.

  • Central Aluminum atom transfers its $3$ valence electrons to three surrounding Chlorine atoms, enabling each Chlorine to complete an octet.

Systematic Nomenclature and Chemical Formula Construction for Ionic Compounds

• Structural Principles of Ionic Compounds:

  • Every binary or ternary ionic compound is constructed from a positive ion (cation) and a negative ion (anion):     $\text{Cation}^+ + \text{Anion}^-$

• Step-by-Step Rules for Constructing Chemical Formulas:

  • Step $1$: Write the chemical symbol of the cation along with its valence charge on the left, followed by the chemical symbol of the anion with its valence charge on the right.

  • Step $2$: Simplify charges or valences by their greatest common divisor if both values are divisible.

  • Example: For $Mg^{+2}$ and $S^{-2}$, the ratio $2:2$ reduces to $1:1$, producing the empirical formula $MgS$.

  • Step $3$: Apply the criss-cross rule: exchange the numerical valence charges so that each becomes the subscript (subindex) of the opposing ion.

  • Subscripts are strictly written without any positive or negative signs.

  • Step $4$: Polyatomic ion formatting rule:

  • When a polyatomic ion requires a subscript of $2$ or greater to balance charges, the polyatomic ion must be enclosed entirely within parentheses, with the subscript positioned outside the closing parenthesis.

  • If the required subscript for a polyatomic ion is $1$, parentheses are omitted and the number $1$ is not written.

• Rules for Naming Ionic Compounds:

  • The cation is always stated first in the chemical name, followed by the anion.

  • Monoatomic Cations: Retain the unaltered elemental name of the metal.

  • If a cation has a unique, invariant oxidation state (such as alkali metals, alkaline earth metals, $Al^{+3}$, $Zn^{+2}$, $Cd^{+2}$, $Ag^{+1}$), no roman numerals are required; simply state its name.

  • Monoatomic Anions: Named by taking the elemental stem of the nonmetal, removing its elemental suffix, and replacing it with the suffix "-ide".

  • Polyatomic Anions: Retain their established standardized names (e.g., sulfate, sulfite, phosphate).

• Fully Worked Examples of Formula Construction and Systematic Naming:

  • Magnesium and Sulfur:

  • Ions: $Mg^{+2}$ and $S^{-2}$

  • Simplification: The charges $+2$ and $-2$ simplify to $1$ and $1$.

  • Criss-cross: Subscripts become $1$ and $1$.

  • Resulting Formula: $MgS$

  • Systematic Name: Magnesium Sulfide

  • Aluminum and Sulfur:

  • Ions: $Al^{+3}$ and $S^{-2}$

  • Simplification: $3$ and $2$ cannot be simplified.

  • Criss-cross: The numerical value $3$ transfers to Sulfur; the numerical value $2$ transfers to Aluminum.

  • Resulting Formula: $Al_2S_3$

  • Systematic Name: Aluminum Sulfide

  • Magnesium and Phosphorus:

  • Ions: $Mg^{+2}$ and $P^{-3}$

  • Criss-cross: Valence $2$ transfers to Phosphorus; valence $3$ transfers to Magnesium.

  • Resulting Formula: $Mg_3P_2$

  • Systematic Name: Magnesium Phosphide

  • Magnesium and Phosphate Polyatomic Ion:

  • Ions: $Mg^{+2}$ and $(PO_4)^{-3}$

  • Criss-cross: Valence $2$ transfers to the phosphate group; valence $3$ transfers to Magnesium.

  • Parentheses Application: Because phosphate is polyatomic and receives a subscript of $2$, parentheses are mandatory: $(PO_4)_2$.

  • Resulting Formula: $Mg_3(PO_4)_2$

  • Systematic Name: Magnesium Phosphate

  • Sodium and Sulfite Polyatomic Ion:

  • Ions: $Na^{+1}$ and $(SO_3)^{-2}$

  • Criss-cross: Valence $2$ transfers to Sodium; valence $1$ transfers to Sulfite.

  • Parentheses Application: Because the subscript assigned to sulfite is $1$, parentheses and the numeral $1$ are omitted.

  • Resulting Formula: $Na_2SO_3$

  • Systematic Name: Sodium Sulfite

  • Ammonium and Phosphate Polyatomic Ions:

  • Ions: $(NH_4)^{+1}$ and $(PO_4)^{-3}$

  • Criss-cross: Valence $3$ transfers to Ammonium; valence $1$ transfers to Phosphate.

  • Parentheses Application: Ammonium receives subscript $3$, requiring parentheses: $(NH_4)_3$. Phosphate receives subscript $1$, so its parentheses are dropped.

  • Resulting Formula: $(NH_4)_3PO_4$

  • Systematic Name: Ammonium Phosphate

  • Sodium and Chlorine:

  • Ions: $Na^{+1}$ and $Cl^{-1}$

  • Simplification / Criss-cross: Direct $1:1$ stoichiometric ratio.

  • Resulting Formula: $NaCl$

  • Systematic Name: Sodium Chloride (cation has a unique valence, stated directly without modification).

Academic Literature and Bibliographic References

• Textual and Curriculum References:

  • Burns, R. ($2002$). Fundamentos de Química. Cuarta Edición. México: Pearson Prentice Hall.

  • Buthelezi, T., Dingrando, L., Hainen, N., Wistrom, C., & Zike, D. ($2008$). Chemistry: Matter and Change. Estados Unidos: McGraw-Hill.

  • Dingrando, L. ($2003$). Química: Materia y Cambio. Colombia: McGraw-Hill.

  • McLaughlin, C., Thompson, M., & Zike, D. ($2002$). Physical Science. USA: Glencoe/McGraw-Hill.

  • Phillips ($2000$). Química: Conceptos y Aplicaciones. Primera Edición. México: McGraw-Hill.

  • Ramírez Regalado, Víctor Manuel ($2013$). Química 1. 2ª edición. México: Editorial Patria.

  • Recio, Francisco ($2008$). Química Inorgánica. México: McGraw-Hill.

  • Silberberg, M. ($2000$). Chemistry: The Molecular Nature of Matter and Change. 2nd Edition. Boston: McGraw-Hill, pp. $277$-$284$, $293$-$307$.

  • Timberlake, K., & Timberlake, W. ($2007$). Basic Chemistry. 2ª edición. Estados Unidos: Pearson.

  • Britannica Editors ($2026$, August $29$). Covalent bond. Encyclopedia Britannica. https://www.britannica.com/science/covalent-bond

  • Britannica Editors ($2026$, September $26$). Ionic bond. Encyclopedia Britannica. https://www.britannica.com/science/ionic-bond