220 likes | 361 Views
Completing the Model of the Atom. Chapter 7 Notes. Objectives. 7.1 Relate emission spectra to the electron configurations of atoms. 7.1 Relate energy levels and orbital's within atoms
E N D
Completing the Model of the Atom Chapter 7 Notes
Objectives • 7.1Relate emission spectra to the electron configurations of atoms. • 7.1 Relate energy levels and orbital's within atoms • 7.2 Distinguish the s,p,d,and f blocks on the periodic table and relate them to an element's electron configuration. • 7.2 Predict the electron configurations of elements using the periodic table
More Electron Configurations Hund’s Rule Pauli Exclusion Principle Aufbau Principle
Quick Warm up • Who is the guy we associate with Electrons and energy levels? • Bohr
Filling in Electrons • Electrons can only fill into certain shells • These shells have different shapes associated with the orbital of the electrons • 4 different shells • S orbital: Circular • P orbital: Dumb bell shape (x, y, z axis) • D orbital: Dumb bell shape (and donut) • F orbital: Dumb bell shape (crazier still)
Electron Orbit Shapes • Electrons fill into different shells • Different types of shells based off of the way the electrons orbit the nucleus
Why are they shapes? • Even though the electron is said to be at a certain location (energy level), the electron is orbiting the nucleus and the shape is a probability of where you will find it • The orbitals drawn correspond to a greater than 90% chance of finding the electron (if you were to take a snap shot)
Filling in Electrons • Each orbital can only hold 2 electrons • Each subset of orbitals has different amounts of orbitals • 1 S orbital per energy level (holds 2 electrons) • 3 P orbitals per energy level (holds 6 ) • 5 D orbitals per energy level (holds 10 ) • 7 F Orbitals per energy level (holds 14 )
Filling in Electrons • Electrons fill into the closest available orbital to the nucleus • Closest orbital corresponding to the lowest energy • 1s22s22p63s23p64s23d104p65s24d105p66s2 • 4f145d106p67s25f146d107p6 • Looks a bit confusing… and would be difficult to memorize… Periodic Table Ally
Another way of looking at it • 3d __ __ __ __ __ • 4s __ • 3p __ __ __ • 3s __ • 2p __ __ __ • 2s __ • 1s __ Each line represents an orbital for electrons to fill in and occupy
Pauli Exclusion Principle • 3p ____ ____ ____ • 3s ____ • 2p ____ ____ ____ • 2s ____ • 1s ____ • Pauli Exclusion Principle: No electrons in the same orbital spin the same direction (denoted by Up and Down arrows)
Rules for Filling in Electrons • 3p ____ ____ ____ • 3s ____ • 2p ____ ____ ____ • 2s ____ • 1s ____ Aufbau Principle: Electrons fill in the lowest energy levels available (Build up)
Hund’s Rule • 3p ____ ____ ____ • 3s ____ • 2p ____ ____ ____ • 2s ____ • 1s ____ Hund’s Rule: If all orbitals aren’t filled, first fill them (same spin as first) before pairing the electrons up (want their own space (Attila the Hun)
Writing Out Electron Configs • Long Hand • Cl (Chlorine) • 1s22s22p63s23p5 • Ca (Calcium) • 1s22s22p63s23p64s2 • Oxygen (O)? • Zinc (Zn)? • Krypton (Kr)?
Review • How many electrons can each orbital have? • What is the Pauli Exclusion principle? • What is Hund’s rule? • What is the aufbau principle? • What is the shape of a “p” orbital?
Practice: Fill in electrons for Ni • 3d __ __ __ __ __ • 4s __ • 3p __ __ __ • 3s __ • 2p __ __ __ • 2s __ • 1s __
Practice: Fill in electrons for Al • 3d __ __ __ __ __ • 4s __ • 3p __ __ __ • 3s __ • 2p __ __ __ • 2s __ • 1s __
Practice • Identify the element by its electron configuration • A) 1s22s22p63s2 • B) 1s22s22p63s23p64s2 • C) 1s22s22p63s23p64s23d104p5 • D) 1s22s22p63s23p64s23d104p65s24d105p66s2 • 4f145d9
Are some electrons more important than others? • When atoms interact, what is really interacting are the electrons (the electron magnetic field) • As new electrons are added, the electrons closer to the nucleus are no longer interacting with other atoms • The outer most electrons are called the • Valence Electrons
Valence Electrons • Only electrons in the S and P orbitals interact with other atoms and account for the molecules chemical reactivity (for the most part) • And not all the S and P electrons, just the S and P electrons in the Highest energy level
Valence Electrons • Example: Sulfur, has an electron configuration of 1s22s22p63s23p4 • The 1s, 2s, and 2p electrons are closer the nucleus and don’t interact 1s22s22p63s23p4 • The highest energy level reached is the 3rd energy level 1s22s22p63s23p4 • We count all the electrons in the S and P at the highest energy level: 6 valence e’s 1s22s22p63s23p4