Atomic Interactions I Lecture (2024) PDF

Atomic Interactions Course: HNDT 1001- General Chemistry for Nutrition Lecturer: Keisha Mascoll Class Attendance Course Code: Course Name: Time: All students are required to scan the QR code and complete the required fields for your class...

Atomic Interactions Course: HNDT 1001- General Chemistry for Nutrition Lecturer: Keisha Mascoll Class Attendance Course Code: Course Name: Time: All students are required to scan the QR code and complete the required fields for your class attendance If your device is not compatible, please download a QR Code Reader from your App Store or Google Play Store  Course Meeting Times and Location: Lecture: Thursday 1:00pm – 3:00pm - MSR3 Lab: Thursday 3:00pm – 5:00pm - MLTC (lab) Tutorial: Friday 9:00am – 10:00am - MSR3 HNDT 1001: General Chemistry for Nutrition ▪ Mode of Delivery: Face-to face ▪ Laboratory Session: Face-to face ▪ Course Rubric: Course Weight Assessment Item Quantity % Labs 5 25 5 weekly written reports on lab work assignments The quizzes will consist of multiple choice, short Quizzes 2 20 answer & calculations The test will consist of multiple choice, short answer Mid-Term Test 1 15 & calculations Duration: 1.5 hrs The test will consist of multiple choice, short answer Final Examination 1 40 & calculations Duration: 2 hrs  Test Dates Course Week Date Duration Format Closed book and will consist of Friday 4th October, Quiz #1 5 2024 1hr multiple choice, short answer questions and calculations Closed book and will consist of Thursday 24th Mid-term 8 October, 2024 1hr 30 mins multiple choice, short answer questions and calculations Closed book and will consist of Thursday 14th Quiz #2 11 November, 2024 1 hr multiple choice, short answer questions and calculations  Laboratory Schedule Week Lab # Title Date 4 1 Mole Ratio & Reaction Stoichiometry 26th September 2024 8 2 Titration of Acids & Bases 24th October 2024 10 3 Determination of Equilibrium Constant 7th November 2024 11 4 Calorimetry 14th November 2024 12 5 Worksheet 21st November 2024  Required/Essential Text 1. Blackman, A., Bottle, SE., Schmid, S., et al. (2019), Chemistry, 4th edition. New Jersey: John Wiley & Sons. ISBN-13 978- 0730363268, ISBN-10: 0730363287 2. McMurry J., Ballantine D., Hoeger C., et al (2016). Fundamentals of General, Organic and Biological Chemistry (Mastering Chemistry). 8th Edition. London: Pearson. ISBN-13 978- 0134015187, ISBN-10: 0134015185 3. Petrucci R., Herring F., Madura J., et al. (2016). General Chemistry: Principles and Modern Applications. 11 Edition. London: Pearson. ISBN-13: 978-0132931281, ISBN-10: 0132931281  Learning Outcomes ▪ Describe the structure of the atom in terms of protons, neutrons, and electrons and express the relative electrical charges and masses of these subatomic particles. ▪ Use chemical symbols together with atomic number and mass number to express the subatomic composition of isotopes. ▪ Describe how elements are organized in the periodic table by atomic number and by similarities in chemical behavior, giving rise to periods and groups. ▪ Identify the locations of metals and nonmetals in the periodic table. ▪ Review of electronic configurations ▪ Distinguish between molecular substances and ionic substances in terms of their composition. ▪ Explain how ions are formed by the gain or loss of electrons and use the periodic table to predict the charges of common ions.  Topics ▪ Atomic Number & Mass Numbers ▪ Isotopes ▪ Periodicity ▪ Chemical Bonding ▪ Covalent Bonding ▪ Ionic Bonding ▪ Metallic Bonding ▪ Valence ▪ Octet Rule ▪ Ionic vs. Covalent Bonding  Atomic & Molecular Prospective Matter is made up of particles. These particles are atoms, ions or molecules. ▪ Atom - The smallest part of an element or compound that can participate in a chemical reaction. Molecule - Groups of atoms held together with a specific connectivity and shape.  Atomic & Molecular Prospective Matter is classified according to their: ▪ State: gas, liquid or solid ▪ Composition: element, compound or mixture Composition: The types of atoms that are present in a compound and the ratio of these atoms (e.g. H2O, C2H6O).  Pure Substance - fixed composition & distinct properties. They are either Elements, elements or compounds. Elements -All atoms are the same kind, elements have only one type of atom. Compounds e.g., oxygen (O2), gold (Au), silicon (Si) and diamond (C). Compound - contains more than one type of atom e.g. water (H2O), ethanol & (C2H6O), sodium chloride (NaCl). Mixtures Mixture - has variable composition and can be separated into component parts by physical methods. They contain more than one kind of molecule, and their properties depend on the relative amount of each component present in the mixture. Molecular View of Elements & Compounds Homogeneous & Heterogeneous Mixtures The composition for both heterogeneous and homogeneous mixtures is variable. Homogeneous Mixture - uniform throughout Gaseous e.g., air Liquid e.g., coffee, vodka, blood Solid e.g., Brass Heterogenous Mixture - non uniform Gaseous e.g., smog Liquid e.g., ice cubes in a drink, sand in water Solid e.g., concrete  Structure of the Atom Position Charge Mass (kg) Relative Mass Protons Nucleus + 1.67*10-27 1 Neutrons Nucleus 0 1.67*10-27 1 Electrons Orbiting Nucleus - 9.1*10-31 1/1840  Atomic & Mass Numbers Atomic Number = the number of protons in the nucleus. # of protons = # of electrons and because they are oppositely charged, it confers neutrality on the atom. All atoms of the same element have the same number of protons. Atomic Mass Number = the sum of the number of protons and neutrons for an atom  Isotopes ▪ Isotopes are different atoms of the same element with different masses. ▪ Isotopes have different numbers of neutrons, thus different mass numbers. Isotopes of Carbon  Uses of Isotopes The use of stable isotopes in nutritional studies is now widespread, and the technique is becoming increasingly popular. Practical applications are numerous and include: Calcium and iron absorption studies, looking at the impacts of ▪ diet ▪ physical activity, ▪ aging, and ▪ medical therapy and supplementation on nutrient metabolism, the measurement of energy cost of pregnancy, studies on the causes of growth faltering in infants investigations into childhood and adult obesity.  Uses of Isotopes Other Practical applications of isotopes: ▪ Metabolic studies ▪ Assess body composition ▪ Protein turnover Isotopes that are utilized during these processes are: ▪ deuterium (2Hydrogen) ▪ 18Oxygen, ▪ 13Carbon ▪ 15Nitrogen These stable isotopes are NOT radioactive and therefore have no adverse biological or physiological effects Periodicity  Major Classifications of Elements Main group or representative elements: ▪ Group 1 A (1): the alkali metals; ▪ Group 2 A (2): the alkaline Earth metals; ▪ Groups 3 A (13), 4 A (14), 5 A (15), and 6 A (16), ▪ Group 7 A (17): the halogens, and ▪ Group 8 A (18): the noble gases. Transition Metals: ▪ Groups 3 B (3) – 2 B (12) ; contains heavy metals. Metalloids (semi-metals): ▪ B, Si, Ge, As, Sb, Te, Po and At Periodicity Less Metallic Trends in the Periodic Table Relative Abundance of Elements in the Human Body ▪ Chemical elements are the building block of life. ▪ The structure of the building blocks which include proteins and nucleic acids, is determined by the proportion and interaction of chemical elements. ▪ The human body is comprised of ~ 99% of just 6 elements: O2, H2, N2, C, Ca, & P. ▪ Another five elements make up about 0.85% of the remaining mass: S, K, Na, Cl, & Mg. ▪ The remaining 0.15% of the human body is comprised of trace elements.  The Electronic Configuration of Atoms Where are electrons found? ▪ Electrons are thought to move around a nucleus in shells or energy levels. ▪ These shells are each assigned a principle quantum number ‘n’ ▪ n=1 to n = ♾ ▪ Each shell is made up of subshells and these subshells are made up of orbitals ▪ Subshells are designated a secondary quantum number ‘l’ and are assigned the letters s, p, d, f, g and h  The Electronic Configuration of Atoms Writing Electronic Configurations Three rules govern the ground state electronic configuration of an atom or an element. 1. Aufbau Principle 2. Pauli Exclusion Principle 3. Hund's Rule  The Electronic Configuration of Atoms 1. Aufbau Principle Electrons in their ground state occupy orbitals of the lowest energy first. 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p etc.  The Electronic Configuration of Atoms 2. Pauli’s Exclusion Principle An orbital can be occupied by only 2 electrons at a time and they must have opposite spin.  The Electronic Configuration of Atoms 3. Hund’s Rule Orbitals of the same energy are singly occupied first with parallel spin before pairing occurs. Electronic Configurations Shapes and Symmetry of Atomic Orbitals An orbital is an area where it is probable that an electron/electron density will be found orbiting a nucleus. ‘s’ orbital ▪ spherical in shape ▪ spherically symmetrical ‘p’ orbital ▪ dumbbell in shape and ▪ has two lobes ▪ electron density is equally distributed in two regions on opposite side of the nucleus Shapes and Symmetry of Atomic Orbitals Chemical Bonds  Bonding Bonding is the force of attraction between oppositely charged particles. Chemical Bonds ▪ Covalent Bonding Protons (+) are attracted to electrons (-) ▪ Ionic Bonding Cations (+) are attracted to anions (-) ▪ Metallic Bonding Protons (+) are attracted to electrons (-) During bonding, atoms tend to gain, lose, or share electrons until they are surrounded by eight valence electrons (the octet rule).  Covalent Bonding This is defined as the force of attraction between pairs of shared electrons and their atomic nuclei. ▪ Sharing of valence electrons between atoms. ▪ Molecules are the product of covalent bonding. ▪ Typically occurs between two non-metals. Covalent Bonding  Properties of Covalent Compounds ▪ Most compounds (are gases, liquid or solid) having covalent bonds exhibit relatively low melting points and boiling points. ▪ They are poor conductors of electricity. ▪ Covalent compounds are not soluble in water.  Ionic Bonding The electrostatic force of attraction between a cation and an anion is known as an ionic/electrovalent bond. ▪ Complete transfer of electrons ▪ Ions are formed ▪ Usually between a metal and a non-metal  Ionic Bonding When atoms lose or gain electrons, they become ions. ▪ Cations (+) ▪ Anions (-) The element’s symbol is followed by a superscript number and a sign that shows the charge on the ion in electron charge units. Ionic Bonding  Properties of Ionic Bonding ▪ Solids with high melting points ▪ They do not conduct electricity when solid. ▪ If they are melted i.e. liquid, they will conduct electricity. ▪ Those which dissolve in water produce solutions which conduct electricity  Metallic Bonding This is the force of attraction between a sea of mobile electrons and the positive nuclei (residual cations) In a metallic structure: There is an overlap of atomic orbitals extending over three dimensions (3D). Electrons: ▪ are delocalized ▪ move freely throughout the structure  Metallic Bonding ▪ The electrons can move freely within these molecular orbitals ▪ Only react with nonmetals ▪ Metals lose electrons and become cations ▪ Metals cannot react with one another. ▪ Compounds of metals are primarily ionic Metallic Bonding  Characteristics of Metals 1. Malleable (bent and shaped without breaking) & ductile pulled (into wires) ▪ The layers of ions in a metallic structure can slide over each other giving rise to these properties. 2. Good conductors of heat and electricity. ▪ If a voltage is applied, the negative delocalised electrons are free to move throughout the metal towards the positive terminal. 3. Shiny appearance; solids, except mercury ▪ When a wave of light hits the metal, the sea of electrons absorb the energy from the light, which makes them vibrate at the atomic level  Octet Rule ▪The octet rule states that main group elements tend to form compounds in such a way that they gain or lose electrons in order to achieve eight valence electrons. ▪Thus the atoms have an electron configuration of a noble gas.  Exceptions to the Octet Rule Not all atoms in a molecule obey the octet rule. These molecules fall into three categories: 1. Electron-deficient molecules have a central atom that has fewer electrons than needed for a noble gas configuration. 2. Hypervalent molecules have a central atom that has more electrons than needed for a noble gas configuration. 3. Odd-electron molecules have an odd number of valence electrons and therefore have an unpaired electron.  Electron-deficient Compounds Be is in group 2, it has 2 valence electrons; Cl has a 7 valence electrons Be forms 2 covalent bonds with Cl, while the Cl atoms achieve their octet during bonding, the Be central atom only has 4 electrons.  Hypervalent Compounds A molecule that the central atom (main group element) deviates from the octet rule by sharing more than 8 electrons These are formed by elements in period 3 or higher, where the central atom can accommodate more than 4 pairs of electrons (octet). They use an expanded valence shell which utilizes empty d orbitals. Odd-Electron Molecule  Ionic Bonding & Covalent Bonding Very few compunds are 100% ionic or 100% covalent. Ionic Character ▪ This occurs in a covalent molecule or bond if the molecule is polar. ▪ The greater the diference in electronegativity of the atoms in the molecule, the greater the dipole moment and the greater the ionic character.  Ionic Bonding & Covalent Bonding Covalent Character The covalent character in ionic bonds or compounds is influenced by the following; 1. Size of the cation 2. Size of the anion 3. Charge of the cation and anion  Ionic Bonding & Covalent Bonding Size of the cation If the cation is small, it will attract the anion's electrons more strongly than a large action. The result is greater polarization. Size of the anion In a large anion, the electrons are further away from the nucleus and hence more loosely held. The electrons can therefore be more easily attracted to and distorted by a small cation. The larger the anion, the more easily it is polarized  Review Topics ▪ Atomic Structure & Composition ▪ Periodic Table & Its Classifications ▪ Characteristics of Metals, Non-Metals & Metalloids ▪ Chemical Formula ▪ Chemical Nomenclature ▪ Common Monoatomic Ions ▪ Common Polyatomic Ions ▪ Formula of Compounds