Electron Configuration CONFIGURED (GET IT??) BY MR. TARUSCIO

Clash of ideas! Is an electron a particle or a wave?

Schrödinger model quantifies electrons into ATOMIC ORBITALS rather than specific energy levels. Orbitals are described with 2 different numbers called Quantum Numbers 1)Principal Quantum Number (n) Integer values that describe the energy of the orbital Larger n means larger average distance of an electron from nucleus (thus larger orbital) 2)Angular Momentum Quantum Number (l) Tells us the “shape” of the orbitals l Name of orbitalspdfgh

Orbital Diagrams

The s orbital has a spherical shape centered around the origin of the three axes in space. s orbital shape

Orbitals of the same shape (s, for instance) grow larger as n increases… Nodes are regions of low probability within an orbital. Sizes of s orbitals

There are three dumbbell- shaped p orbitals in each energy level above n = 1, each assigned to its own axis (x, y and z) in space. P orbital shape

Things get a bit more complicated with the five d orbitals that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells ” …and a “dumbell with a donut”! d orbital shapes

Shape of f orbitals

Orbital filling table Label Your Periodic Table

Electron Configuration 1s11s1 row # shell # possibilities are rows subshell possibilities are s, p, d, or f 4 subshells group # # valence e- possibilities are: s: 1 or 2 p: 1-6 d: 1-10 f: 1-14 Total e- should equal Atomic # What element has an electron configuration of 1s 1 ?

The Order of Orbitals  1s,  2s, 2p,  3s, 3p,  4s, 3d,4p,  5s, 4d, 5p,  6s, 4f, 5d, 6p,  7s, 5f, 6d, 7p,  (8s, 5g, 6f, 7d, 8p, and 9s)

PRACTICE!!!

RULES!! Memorize These!!  Three rules (To MEMORIZE)  Aufbau: Electrons fill orbitals starting in the lowest energy levels and moving out.  Pauli: No two electrons can have the same spin and occupy the same orbital.  Hunds: Electrons fill each orbital singly before any orbital get a second electron.

Details  Valence electrons- the electrons in the outermost energy levels (not d).  Core electrons- the inner electrons  Hund’s Rule- The lowest energy configuration for an atom is the one have the maximum number of unpaired electrons in the orbital.  C 1s 2 2s 2 2p 2

ElementConfiguration notation Orbital notationNoble gas notation Lithium1s 2 2s 1 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 1 Beryllium1s 2 2s 2 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 Boron1s 2 2s 2 p 1 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 1 Carbon1s 2 2s 2 p 2 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 2 Nitrogen1s 2 2s 2 p 3 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 3 Oxygen1s 2 2s 2 p 4 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 4 Fluorine1s 2 2s 2 p 5 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 5 Neon1s 2 2s 2 p 6 ____ ____ ____ ____ ____ 1s 2s 2p [He]2s 2 p 6

Shorthand Notation  A way of abbreviating long electron configurations  Since we are only concerned about the outermost electrons, we can skip to places we know are completely full (noble gases), and then finish the configuration

Shorthand Notation  Step 1: Find the closest noble gas to the atom (or ion), WITHOUT GOING OVER the number of electrons in the atom (or ion). Write the noble gas in brackets [ ].  Step 2: Find where to resume by finding the next energy level.  Step 3: Resume the configuration until it’s finished.

Shorthand Notation  Chlorine  Longhand is 1s 2 2s 2 2p 6 3s 2 3p 5 You can abbreviate the first 10 electrons with a noble gas, Neon. [Ne] replaces 1s 2 2s 2 2p 6 The next energy level after Neon is 3 So you start at level 3 on the diagonal rule (all levels start with s) and finish the configuration by adding 7 more electrons to bring the total to 17 [Ne] 3s 2 3p 5

Electromagnetic Radiation

Properties of Waves All electromagnetic waves travel at the same speed The speed of light: 300,000 km/s trough crest

Properties of Waves Wavelength (length/cycle) Wavelength ( ): the length of one complete cycle trough crest

Properties of Waves Wavelength (length/cycle) Amplitude: 1/2 height between trough and crest Amplitude trough crest

Properties of Waves Wavelength (length/cycle) Frequency ( ): the number of cycles/second Amplitude trough crest

Speed = wavelength x frequency c = (length/second) = (length/cycle) x (cycle/second) Hence, = c / and = c /

Examples  What is the wavelength of light with a frequency 5.89 x 10 5 Hz?  What is the frequency of blue light with a wavelength of 484 nm?

Light  Made up of electromagnetic radiation  Waves of electric and magnetic fields at right angles to each other.

Copyright © Houghton Mifflin Company. All rights reserved. 7–33 Classification of Electromagnetic Radiation

Hydrogen spectrum  Emission spectrum because these are the colors it gives off or emits  Called a line spectrum.  There are just a few discrete lines showing 410 nm 434 nm 486 nm 656 nm Spectrum

The Bohr Ring Atom  He didn’t know why but only certain energies were allowed.  He called these allowed energies energy levels.  Putting energy into the atom moved the electron away from the nucleus  From ground state to excited state.  When it returns to ground state it gives off light of a certain energy

The Bohr Ring Atom n = 3 n = 4 n = 2 n = 1

An excited lithium atom emitting a photon of red light to drop to a lower energy state.

An excited H atom returns to a lower energy level.

Periodic Trends

Sizes of Atoms Difficult to define atomic radii for single atoms because the outside of the electron cloud.

Sizes of Atoms The non-bonding atomic radius is defined as one-half of the distance between two atoms when they collide.

Sizes of Atoms Bonding atomic radius tends to… …decrease from left to right across a row …increase from top to bottom of column

Sizes of Ions  Ionic size depends upon:  Nuclear charge.  Number of electrons.  Orbitals in which electrons reside.

Ionization Energy  Amount of energy required to remove an electron from the ground state of a gaseous atom or ion.  First ionization energy is that energy required to remove first electron.  Second ionization energy is that energy required to remove second electron, etc.

Ionization Energy  It requires more energy to remove each successive electron.  When all valence electrons have been removed, the ionization energy shows a HUGE increase.

Electronegatvity  Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.  The Pauling scale is the most commonly used.  Fluorine (the most electronegative element) is assigned a value of 4.0  Values range down to cesium and francium which are the least electronegative at 0.7.

Electron Affinity  Electron affinity is defined as the change in energy of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion.  The neutral atom's likelihood of gaining an electron

Do Now!  Define:  Electronegativity  Ionic Radius  Ionization energy  What appears to be the trend in atomic radius as you move from left to right in a row?  What appears to be the trend in atomic radius as you move down a column?