Presentation on theme: "Chemistry Chapter 4 Arrangement of Electrons in Atoms"— Presentation transcript:
1 Chemistry Chapter 4 Arrangement of Electrons in Atoms electromagnetic radiation- a form of energy that exhibits wavelike behavior as it travel through spacewavelength ( λ )- the distance between corresponding points on adjacent wavesfrequency ( f ) the number of waves that pass through a specific point in a specific timehertz ( Hz )- a frequency of one wave per second
2 Speed of Electromagnetic Radiation The speed ( c ) of all wavelengths of electromagnetic radiation = 3.0 x 108 m/s.c = fλIF “c” is a constant, then wavelength varies inversely with the frequency of electromagnetic radiation.
3 Photoelectric Effectphotoelectric effect- the emission of electrons from a metal when light shines on that metalquantum- the minimum amount of energy that can be gained or lost by an atomphoton- a quantum of light energyground state- the lowest energy state of an atomexcited state- a higher energy state
4 Spectraline-emission spectrum- The specific colors (frequencies) of light emitted when an atom returns to the ground state from the excited state.It can be seen when the light is separated by a prism and will give an element a specific spectrum.continuous spectrum- the emission of a continuous range of frequencies of electromagnetic radiation
5 Section 2 The Quantum Model of the Atom Heisenberg Uncertainty Principle- it is impossible to determine simultaneously both the position and the velocity of an electronQuantum theory- describes mathematically the wave properties of electronsorbital- a three-dimensional region around the nucleus that indicates the probable location of an electronEach orbital can contain a maximum of 2 electrons.
6 Atomic Orbitals and Quantum Numbers quantum numbers- specify the properties of atomic orbitals and the properties of the electrons in the orbitalsprincipal quantum number- indicates the main energy level occupied by an electronthe number of electrons possible per energy level = 2 n2 where n = energy levelangular momentum quantum number- indicates the shape of an orbitals, p, d, & fmagnetic quantum number- indicates the orientation of an orbital around the nucleus of an atomspin quantum number- indicates the two fundamental states of spin of an electron
7 OrbitalsThere is a single “s” orbital per energy level for a maximum of 2 “s” electrons per level.the energy level for “s” orbitals = the period numberThere are 3 “p” orbitals per energy level for a maximum of 6 “p” electrons per level.the energy level for “p” orbitals = the period numberThere are 5 “d” orbitals per energy level for a maximum of 10 “d” electrons per level.the energy level for “d” orbitals is the period number minus 1There are 7 “f” orbitals per energy level for a maximum of 14 “f” electrons per level.the energy level for “f” orbitals is the period number minus 2
8 Section 3 Electron Configurations electron configuration- the arrangement of electrons in an atomRules governing electron configuration:Aufbau principle- an electron occupies the lowest energy orbital that can receive itPauli exclusion principle- no two electrons in the same atom can have the same four quantum numbersHund’s rule- orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron
9 Electron Configuration Notation ORBITAL NOTATION: See pgELECTRON-CONFIGURATION NOTATION:See pg 113[Ne] 3s23p4Do Practice #1 & #2 on page 113.
10 Elements & Electron Configurations 1st period elements- see periodic table2nd period elements3rd period elementsnoble-gas configuration- refers to an outer main energy level occupied by eight electrons ( ns2np6 in most cases)4th period elements5th period elementsDo Practice #1-4 on page 121.
11 Elements & Electron Configurations Elements of the 6th and 7th periods contain “f” orbitals.Do Practice #1 & 2 on page 122.Do Section Review #5 on page 122.Do Chapter review #33, 36, & 38 on pagesReview for Chapter 4 Test
12 Chapter 4 Test- (40 questions) Know the meaning of the formula c = fλ .Know the meaning of hertz, wavelength, photon, photoelectric effect, ground state, excited state.Know how EMR travels through space.Know how a line spectrum is produced.Know what must happen for an electron to move between the ground and excited states.Understand the Bohr model of atoms.Know the definition of electron cloud, the quantum numbers, orbital.Know how to calculate number of electrons per energy level.
13 Chapter 4 TestUnderstand the differences in the energies of different orbital sublevels.Know Aufbau principle, Hund’s rule, & Pauli exclusion principle.Identify elements using their electron configuration notation.Determine the electron configuration notation of elements.Know the definition of a noble gas.Write an electron configuration notation using an element’s orbital notation.Identify an element using its orbital notation diagram.