Course Material 2 - Atomic Structure and the Periodic Table.pdf

Atomic Structure and the Periodic Table Learning Outcomes Understand the internal structure of an atom, distinguishing between protons, neutrons, and electrons, and their respective roles within the atom. Explain how atomic number and mass number differentiate elements and isotopes. Ap...

Atomic Structure and the Periodic Table Learning Outcomes Understand the internal structure of an atom, distinguishing between protons, neutrons, and electrons, and their respective roles within the atom. Explain how atomic number and mass number differentiate elements and isotopes. Apply the periodic law to understand the organization and trends within the periodic table and understand the properties of metals and nonmetals. Determine the electron configuration of an element using orbital diagrams and explain its connection to the periodic table. Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Atomic Structure consist of an extremely small, positively charged nucleus surrounded by a cloud of negatively charged electrons negatively charged particles positively charged particles e = 9.109 x 10-28 g no charge or neutral particles p = 1.673 x 10-24 g n = 1.675 x 10-24 g center of the atom Atomic Structure What is the charge of the nucleus? Atomic Structure What is the charge of the atom? Atomic Structure What are you feeling right now? Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Atomic Number And Atomic Mass Number No. of protons = 3 No. of neutrons = 4 no. of protons = no. of electrons No. of electrons = 3  Complete the table. Element Atomic Mass Atomic No. No. of No. of No. of No. Protons Electrons Neutrons 55 25 48  Write the Standard Notation. Niobium Cesium Krypton Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Isotopes have the same number of protons but differ in the number of neutrons have same atomic number(Z) but different mass number (A)  Write the Standard Notation. Isotope : isotope with 1 isotope with 3 fewer neutron more neutron Relative Atomic Mass the average mass of one atom of all the naturally occurring isotopes of a particular chemical element, expressed in atomic mass units 1. The element chlorine has two isotopes, Chlorine-35 and Chlorine-37. The abundance of these isotopes when they occur naturally is 75% Chlorine-35 and 25% Chlorine-37. Calculate the average relative atomic mass for Chlorine. Relative Atomic Mass Step 1: Write the given. Step 2: Calculate the mass contribution of the isotopes. Cl-35 = 75% Abundance Mass Contribution = (% Abundance) * (Atomic Cl-35 = 35 amu mass) Cl-37 = 25% Abundance 75 Cl-35 = x 35amu = 26.25 amu 100 Cl-37 = 37 amu 25 Cl-37 = x 37amu = 9.25 amu 100 Relative Atomic Mass Step 3: Add the mass contribution per isotope. Relative Atomic Mass = 26.25 amu + 9.25 amu = 35.5amu 35.5amu Calculate the atomic mass. Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Who likes to play a jigsaw = Element puzzle? Dmitri Mendeleev  Periodic Table Group Period Period 1 horizontal row of elements in the periodic 2 table 3 Period 1 to 7 4 5 Group 6 vertical column of elements in the periodic 7 table Group 1 to 18 Group IA to VIIIA Group IB to VIIIB IA IIA VIIA VIIIA  Periodic Table Group Period 1 2 3 4 What is the element? 5 a. Located in both Period 3 and Group 6 IVA 7 IA IIA VIIA VIIIA  Periodic Table Group Period 1 2 3 4 What is the element? 5 b. The Period 4 noble gas 6 7 IA IIA VIIA VIIIA Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Characteristics of Metals and Nonmetals  Periodic Table Locations for Metals and Nonmetals Semi-metal or Metalloids Nonmetals Metals  Identify the nonmetal in each of the following sets of elements. a. S, Na, K b. Cu, Li, P c.Be, I, Ca d. Fe, Cl, Ga Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Electron Configuration the arrangement of electrons in orbitals around an atomic nucleus Electron Configuration Diagram  How to write electron configuration? 1. Determine the Total Number of Electrons o Find the atomic number of the element 2. Know the Order of Filling Orbitals o Use the electron configuration diagram o Add a superscript to indicate the number of electrons in that subshell  Write the electron configuration of Aluminum. 1. Determine the Total Number of Electrons o Find the atomic number of the element Write the electron configuration of Aluminum. 2. Know the Order of Filling Orbitals Use the electron Add a superscript to indicate the configuration diagram number of electrons 1s 2s 2p 3s 3p 2 2 6 2 1 Note: Maximum electron for s is 2 and for p is 6 Write the electron configuration of Cobalt. Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Electron Shells The main energy levels in an atom, designated by the principal quantum number (n) Electron Subshells a region of space within an electron shell that contains electrons that have the same energy (s, p, d, f) Electron Orbitals 2e 6e 10e 14e s p d f 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e 2e Quantum Numbers a set of numbers used to describe the position and energy of the electron in an atom Principal Quantum Number (n) – Size Angular Momentum Quantum Number (ℓ) – Shape Magnetic Quantum Number (mℓ) – Orientation Spin Quantum number(ms) - Direction PRINCIPAL QUANTUM NUMBER (n) Main Energy 1s 2s 2p 3s 3p 2 2 6 2 1 Level n=3 Angular Momentum Quantum Number (ℓ) spherical polar four-leaf clover tetrahedral (ℓ=0) (ℓ=1) (ℓ=2) (ℓ=3) Magnetic Quantum Number (mℓ) No. of Subshells m Illustration Orientation s 1 0 p 3 -1, 0, 1 d 5 -2, -1, 0, 1, 2 f 7 -3, -2, -1, 0, 1, 2, 3 Spin Quantum Number (ms) two electrons present in an orbital always have opposite spins Summary Shell Subshell Subshell No. of Number of Total Orientation (ml) Spin (ms) (n) Notation (ℓ) Orbitals electrons Electrons 1 1s 0 1 0 +½ or -½ 2 2 2s 0 1 0 +½ or -½ 2 2 8 2p 1 3 -1, 0, +1 +½ or -½ 6 3s 0 1 0 +½ or -½ 2 3 3p 1 3 -1, 0, +1 +½ or -½ 6 18 3d 2 5 -2, -1, 0, +1, +2 +½ or -½ 10 4s 0 1 0 +½ or -½ 2 4p 1 3 -1, 0, +1 +½ or -½ 6 4 32 4d 2 5 -2, -1, 0, +1, +2 +½ or -½ 10 4f 3 7 -3, -1, 0, +1, +2, +3 +½ or -½ 14 Rules in assigning electrons to various shells, subshells, and orbitals. Aufbau’s principle The filling of electrons should take place in accordance with the ascending order of energy of orbitals. Hund’s rule of maximum multiplicity In the case of filling degenerate (same energy) orbitals, all the degenerate orbitals have to be singly filled first, and then, only pairing has to happen. Pauli’s exclusion principle No two electrons can have all four quantum numbers to be the same, or if two electrons have to be placed in an energy state, they should be placed with opposite spins.  Determine the quantum numbers of Aluminum. Principal Quantum Number (n) Consider 3p1 n=3 1s22s22p63s23p1  Determine the quantum numbers of Aluminum. Angular Momentum Magnetic Quantum Quantum Number (ℓ) Number (mℓ) sℓ=0 Consider 3p1 Consider 3p1 pℓ=1 dℓ=2 ℓ=1 fℓ=3 mℓ = -1  Determine the quantum numbers of Aluminum. Magnetic Quantum Quantum Numbers Number (mℓ) ▪ n=3 Consider 3p1 ▪ ℓ=1 +½ Upward ▪ mℓ = -1 -½ Downward ▪ ms = +½ ms = +½  Determine the quantum numbers of Cobalt. Quantum Numbers 1s2 2s2 2p6 3s2 3p6 4s2 3d7  Give the element described by these quantum numbers. Quantum Numbers ▪ n=2 ▪ ℓ=1 ▪ mℓ = -1 ▪ ms = -½ Topic Outline Internal Structure of an Atom Atomic Number and Mass Number Isotopes and Atomic Masses The Periodic Law and the Periodic Table Metals and Nonmetals Electron Configuration Electron Arrangements Within Atoms and Orbital Diagrams The Electronic Basis for the Periodic Law and the Periodic Table Periodic Law states that the physical and chemical properties of elements are periodic functions of their atomic numbers Group of Elements Periodic Trends Elements with similar Elements exhibit recurring chemical properties are patterns in properties such grouped together and share as atomic radius, ionization similar electron energy, electron affinity, and configurations and valence electronegativity across the electron arrangements periodic table Group of Elements Halogen Group Classification of Elements Periodic Trends Atomic Radius Metallic Character half the distance between adjacent the tendency of an element to lose atoms of the same element in a molecule electrons and form positive ions or cations Increases Increases Periodic Trends Non-metallic Character Ionization Energy the tendency of an element to accept the amount of energy required to electrons and form negative ions or remove an electron from an isolated anions atom or molecule Increases Increases Periodic Trends Electron Affinity Electronegativity the amount of energy liberated when a measure of an atom's ability to an electron is added to a neutral atom attract shared electrons to itself to form a negatively charged ion Increases Increases Atomic Number And Atomic Mass Number INCREASES Non-Metallic Character Ionization Energy Electron Affinity Electronegativity INCREASES Atomic Radius Metallic Character  Which of the following is the most electronegative? a.Zn b.Fe c. K d.Cl  Which of the following has the least non- metallic character? a.Na b.Ga c. Sr d.Mg  Arrange based on increasing Electron Affinity. Te Cd H Po End of Presentation