final GRP 6 CHEN 804 The Role of Electronic Configuration in Chemical Reactions.pptx
- 1. THE ROLE OF ELECTRONIC CONFIGURATION IN CHEMICAL REACTIONS (GROUP 6) ATERM PAPER GROUP PRESENTATION IN ADVANCED CHEMICAL REACTION ENGINEERING (CHEN 804) BY P23EGCE80.. – ODIRI ORAPOGHENOR P23EGCE8008 – IDRISYUSUF NOVEMBER 2024
- 2. OUTLINE • Introduction to Atomic Structure • Valence Electrons • Octet Rule • Types of Chemical Bonds • Periodic Trends • Electronic Configuration influence on Chemical Reactions • Catalysts • Conclusion
- 3. INTRODUCTION TO ATOMIC STRUCTURE •Atoms can join together to form molecules, which make up most objects. Different elements (e.g. oxygen, carbon, uranium) are made up of different types of atoms. An atom is the smallest unit of an element that will behave as that element. •Atoms consist of an extremely small, positively charged nucleus surrounded by a cloud of negatively charged electrons. Although typically the nucleus is less than one ten-thousandth the size of the atom, the nucleus contains more that 99.9% of the mass of the atom.
- 4. VALENCE ELECTRONS •Definition: •Valence electrons are the electrons in the highest occupied principal energy level of an atom. •Role: •Determine reactivity and bonding. •Example: •Ionic bond of Sodium (Na) and Chlorine (Cl) forming NaCl. •Covalent bond of Carbon (C) and Hydrogen (H)
- 5. THE OCTET RULE •Concept: •The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. This octet can be made up by own electrons and some electrons which are shared. Thus, an atom continues to form bonds until an octet of electrons is made. (E.g. Na+ and Cl- •Impact on Bonding: •Drives the formation of ionic and covalent bonds.
- 6. TYPES OF CHEMICAL BONDS •Ionic Bonds: •Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion. Ionic bonds require an electron donor, often a metal, and an electron acceptor, a nonmetal. E.g. NaCl •Covalent Bonds: •Covalent bonding is the sharing of electrons between atoms. This type of bonding occurs between two atoms of the same element or of elements close to each other in the periodic table. This bonding occurs primarily between nonmetals. •……
- 7. CONTD… •Metallic Bonds: •Metallic bonding joins a bulk of metal atoms. •A metallic substance may be a pure element (e.g. aluminum foil, copper wires), or it may be a mixture of two or more elements in an alloy (e.g. brass instruments, "white gold" jewelry). •Involves a "sea" of delocalized electrons around metal cations, contributing to the conductivity and malleability of metals. •Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms.
- 8. PERIODIC TRENDS •Groups and Periods: •Periodic trends are patterns in the periodic table that illustrate the properties of elements in groups or periods. These trends are based on the similar electron configurations of elements within the same group or period. Some examples of periodic trends in groups include: •Electronegativity: •Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. •High electronegativity = strong attraction. •Ionization Energy: •The ionization energy is the quantity of energy that an isolated, gaseous atom in the ground electronic state must absorb to discharge an electron, resulting in a cation. •Decreases down a group because it's easier to remove an electron from a larger orbital •Low ionization energy = high reactivity. •Electron Affinity: •Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. In other words, the neutral atom's likelihood of gaining an electron. •Decreases down a group because it's more favorable to place electrons into lower energy orbitals •High electron affinity = likelihood to gain electrons.
- 9. INFLUENCE ON CHEMICAL REACTIONS •Redox Reactions: •These reactions involve the transfer of electrons. Understanding the electronic configuration helps predict which substances will act as oxidizing agents (accept electrons) or reducing agents (donate electrons). •Oxidation •When an atom loses electrons, its oxidation number increases and its electronic configuration changes. For example, a sodium atom with an electronic configuration of 2,8,1 loses an electron to form a sodium ion (Na+) with an electronic configuration of 2,8. •Reduction •When an atom gains electrons, its oxidation number decreases and its electronic configuration changes. For example, a chlorine atom with an electronic configuration of 2,8,7 gains an electron to form a chloride ion (Cl-) with an electronic configuration of 2,8,8.
- 10. INFLUENCE ON CHEMICAL REACTIONS (CONTD) •Acid-Base Reactions: •Transfer of protons (H ions). ⁺ •In an acid-base reaction, the electronic configuration of the reactants and products is determined by the transfer of electrons between the acid and base: •Lewis theory •In the Lewis theory of acid-base reactions, acids accept electron pairs, while bases donate them. The reaction of a Lewis acid and a Lewis base produces a coordinate covalent bond, where the Lewis base donates its electrons to form the bond. •General acid-base reaction •The general equation for an acid-base reaction is ACID(aq) + BASE(aq) HO(l) + SALT(aq) or (s). The ⟶ driving force for this reaction is the formation of water. •Gas-forming acid-base reaction •The general equation for a gas-forming acid-base reaction is ACID(aq) + NaHCO or NaCO(aq) HO(l) + ⟶ CO(g) + SALT(aq) or (s). The driving force for this reaction is the formation of gas.
- 11. INFLUENCE ON CHEMICAL REACTIONS (CONTD) •Combustion Reactions: •Reaction with oxygen, forming oxides. •The electronic configuration of atoms is related to combustion reactions in a few ways: •Atoms with incomplete shells are unstable •Atoms with incomplete electron shells are reactive and unstable. When atoms combine, they achieve a full electron configuration, which makes them stable and releases energy. •Valence electrons •The outermost orbitals of an atom are called valence electrons, and they are responsible for most of an element's chemical behavior. •Open and closed shells •A closed shell is a completely filled valence shell, which is very stable. An open shell is a valence shell that is not completely filled. In molecules, an open shell means there are unpaired electrons.
- 12. CATALYSIS •Definition: •Substances that speed up reactions without being consumed. •Unique configurations make certain elements effective catalysts. •Surface Catalysis (Heterogeneous Catalysis) •Transition Metals: Many catalysts are transition metals or their compounds. Transition metals have partially filled d-orbitals, which allow them to form variable oxidation states and complex with reactants. Example: Platinum (Pt) in catalytic converters. The electronic configuration allows it to adsorb and activate molecules like CO and NOx. Surface Interaction: The electronic configuration of the metal surface influences how well it can adsorb reactant molecules. A good catalyst has an electronic structure that allows it to form temporary bonds with reactants, lowering the activation energy for the reaction.
- 13. CATALYSIS (CONTD) • Homogeneous Catalysis • Metal Complexes: In homogeneous catalysis, metal ions or complexes dissolved in solution catalyze the reaction.The electronic configuration of the central metal ion determines its ability to form coordination complexes with reactants. • Ligand Effect: The ligands surrounding the metal ion in a catalyst can influence its electronic configuration and reactivity. By altering ligands, chemists can fine-tune the electronic properties of the catalyst.
- 14. CATALYSIS (CONTD) • Enzyme Catalysis (Biocatalysis) • Enzymes are biological catalysts with active sites where reactions occur. The electronic configuration of amino acids in the active site, along with any metal cofactors, plays a key role in substrate binding and reaction rate. • Example: Cytochrome P450 enzymes contain a heme group with iron (Fe), whose electronic configuration allows it to participate in redox reactions. • Promoters: Substances that enhance the effectiveness of a catalyst. They can alter the electronic configuration of the catalyst or its environment, making it more active.Example: Potassium (K) as a promoter in ammonia synthesis on iron catalysts. • Inhibitors: Substances that decrease the effectiveness of a catalyst. They often interact with the catalyst’s active sites, changing its electronic configuration or blocking reactant access.
- 15. CONCLUSION •Understanding electronic configuration is essential for predicting the behavior of elements in chemical reactions. It provides insights into reactivity, bond formation, molecular geometry, periodic trends, redox processes, and catalysis. This knowledge is fundamental in fields ranging from material science to pharmaceuticals.
- 16. THANK YOU
- 17. 1. Vollhardt, K. Peter C., and Neil E. Schore. Organic Chemistry Structure and Function. New York: W. H. Freeman, 2007. 2. Petrucci, Ralph H. General Chemistry: Principles and Modern Applications. Upper Saddle River, NJ: Pearson Education, 2007. 3. Brown, Theodore L., Eugene H. Lemay, and Bruce E. Bursten. Chemistry: The Central Science. 6th ed. Englewood Cliffs, NJ: Prentice Hall, 1994. 4. Ed Vitz (Kutztown University), John W. Moore (UW-Madison), Justin Shorb (Hope College), Xavier Prat-Resina (University of Minnesota Rochester), Tim Wendorff, and Adam Hahn.