Ch. 11 Notes---Modern Atomic Theory Atomic Models (1) Model: a ball of (+) charge containing a number of e- no ________________ often described as the “________ _______________” atom. (2) Model: a ____________ of (+) charge surrounded by a number of e- no _____________ and no e- orbitals Thomson nucleus plum pudding Rutherford nucleus neutrons

Atomic Models (3) Model: a nucleus of (+) charge that also contains ______________ nucleus is encircled by e-’s located in definite orbits (or paths). e-’s have ___________ energies in these orbits e-’s do not lose energy as they orbit the nucleus (4) Mechanical Model ( Wave Mechanical Model) no definite ____________ to the e- path (“fuzzy” cloud) orbits of e-’s based on the _________________ of finding the e- in the particular orbital shape. Bohr neutrons fixed Quantum shape probability

Bohr Atomic Model

Bohr Atomic Model

Quantum Mechanical Model

Quantum Mechanical Model

Quantum Mechanical Model

Energy Levels Diagram: (Fig. 11.10) The energy levels in an atom are sort of like _________ of a ladder. The more energy an electron has, the __________ away from the nucleus it usually will be. The energy levels are not evenly spaced. They get ___________ together as you travel farther away. To move from one “rung” to another requires a “____________” of energy. rungs farther “excited state” closer quantum “groundstate”

continuous energy levels quantized energy levels Figure 11.15: The difference between continuous and quantized energy levels. continuous energy levels quantized energy levels

most probable location Quantum Numbers Describe the ______________ of the e-’s around the nucleus. Quantum #’s are sort of like a home _____________ for the electron. This information about the location of the e-’s in an atom can be used to: (1) determine chemical & physical _____________ for the elements. (2) show how the _______________ __________ is organized. (3) show _____ and _____ elements combine to form compounds. most probable location address properties Periodic Table how why

The Four Quantum Numbers Principal Q. # (n): Describes the _____________ that the electron is from the nucleus. The bigger the number, the ___________ away the electron is. Example: (1=closest, 2, 3, 4...farther away) These distances are sometimes called _______________ ______________ ____________. distance farther principal energy levels 1 2 3 nucleus

Orbital Q. # (l ): Describes the __________ of the electron’s path around the nucleus with a letter: (s, p, d, & f) These are sometimes called “_____________”. s=_____________ cloud; p=_____________ or a 3-D figure 8; shape sublevels spherical ellipsoid

d & f orbital shapes are complex ________- _______________ ellipsoids, and some d’s and f’s are an ellipsoid with a doughnut or two around the middle. All of these orbital shapes are based on the probability of finding the electron in the cloud. d - orbitals criss crossing f - orbitals

Figure 11.22: How principal energy levels can be divided into sublevels.

A Way to Visualize s, p, d, and f sublevels

Magnetic Q. # (m): tells how many _________________ in 3-D there are about the nucleus for each orbital shape. s=___ orientation p= ___ orientations... (x, y, and z) d= ___ orientations f= ___ orientations The orientations are represented with a line or a box. Examples: ___ This means a __________ orbital at a distance of 1s “__” (close) to the nucleus. This orbital is centered about the x, y, and z axis. □ □ □ This represents an ___________ orbital with its 4p ____ possible orientations at a distance of “___” from the nucleus. orientations 3 1 5 7 spherical 1 ellipsoid 3 4

Figure 11.23: Principal energy level 2 shown divided into the 2s and 2p sublevels

Spin Q. # (s): describes how the electron in an orientation is spinning around the nucleus. This spin can be thought of as “____” or “________”. (Some like to imagine it spinning “clockwise” and “counterclockwise”.) The spin is represented as an ___________ in the direction of the spin. Example: ↑ This represents one electron in a _________ 2s orbital with spin “____” at a distance of “___” from the nucleus. Remember, the four quantum numbers tell us the location, or “address” of each electron in an atom. This information is vital in understanding the layout of the Periodic Table and the reasoning behind why and how atoms form bonds. up down arrow spherical up 2

Electron Configurations Electron configurations are notations that represent the four Quantum #’s for all of the electrons in a particular atom. Here are the rules for these notations: Rule #1 (Aufbau Principle): Electrons fill ________ energy orbitals first. Examples: 1s would be filled before ____ 3s would fill before ____ lowest 2s 3p

Electron Configurations Silicon ↑ ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ (Energy Level Diagram) ↑ ↓ 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…

Rule #2: Only ___ electrons can fit into each orientation. Example: ___ ___ not ____ 1s 2s 1s Rule #3 (Pauli Exclusion Principle): Electrons in the same orientation have ______________ spin. Example: ___ not ___ 1s 1s Rule #4 (Hund’s Rule): “_______________ rule”---> Every “□” in an orbital shape gets an electron before any orientation gets a second e-. Example: □□□ not □□□ 2p 2p 2 ↑ ↓ ↑ ↑ ↓ ↑ opposite ↑ ↓ ↑ ↑ Monopoly ↑ ↑ ↑ ↑ ↓ ↑

Example: ___ ___ ___ ___ ___ ___ 5s 4d becomes ___ ___ ___ ___ ___ ___ Rule #5: The Exceptions Half-filled or completely filled d & f sublevels have ________ energies and are more stable than partially filled d’s and f’s. This means that an atom can “borrow” one of its “s” electrons from the previous orbital to become more stable. Example: ___ ___ ___ ___ ___ ___ 5s 4d becomes ___ ___ ___ ___ ___ ___ 5s 4d Because the 4d sublevel is now full, the atom is at a ________ energy state and therefore _________ stable. lower ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ ↓ ↑ lower more

Electron Configurations Practice Problems: Write the electron configuration notation for each of the following atoms: Hydrogen Carbon Iron Bromine Shorthand Method: Assumes we already know about the # of □. H C Fe Br

How Electron Configurations Relate to the Organization of the Periodic Table

Figure 11.31: Orbitals being filled for elements in various parts of the periodic table.

Electron Configurations & Properties How do electron configurations relate to the chemical and physical properties of an element? All elements with the _________ outer shell e- configurations have ________ properties. This means that elements in the same ____________ group have similar properties. Examples: (1) Li, Na, K, Rb, and Cs all have __ lone “__” e- for their last orbital... (_____, _____, _____, etc.) This makes all of them ___________ reactive. They all react with __________ to produce hydrogen gas. (2) Ne, Ar, Kr, Xe, and Rn all have the outer energy level completely __________ with electrons...(________, ________, ________, etc.) This makes all of them ______________. They do not produce __________________! same similar vertical 1 s 2s1 3s1 4s1 very water filled 2s2 2p6 3s2 3p6 4s2 4p6 inert compounds

More Practice Problems (1) Which element has its last electron as a 4p5? ___________ (2) Which elements are similar in properties as Bromine? __________ (3) What would the outer shell electron configuration look like for the element underneath Radon, (Rn)? (4) Which electron is added after 6s2? ________ (5) Which element would “borrow” a 5s electron to get a half-filled “d” sublevel? ___________ (6) What is the shape of the last orbital filled in Calcium, (Ca)? _____ (7) How many electrons are in the last “p-orbital” of Sulfur, (S)? ____ Bromine F, Cl, I, At …7s2 5f14 6d10 7p6 4f1 Mo sphere 4

Electromagnetic Radiation Any wave of energy traveling at a speed of ___________ is called electromagnetic radiation. There are many types of electromagnetic radiation and each type has a different _______________ and _______________. Here are the types of electromagnetic radiation from longest to shortest wave or lowest to highest frequency. These are also in order from lowest to highest energy. light frequency wavelength

Electromagnetic Radiation

Electromagnetic Radiation (1) Radio Waves -- used in __________________ (2) Microwaves-- broadcasts TV signals and used to _____ _______. (3) Infrared (IR) -- we feel this as _____; _________ & ______ can “see” this. communications cook food heat Snakes owls infrared image of a cat infrared image of heating pipes under a floor

Infrared Vision

Electromagnetic Radiation (4) Visible Light -- the only radiation we can detect with our eyes. It can be separated into the colors of the spectrum with a __________. ROYGBIV (5) Ultraviolet (UV) -- gives you a _____________; _________ can “see” this; some of this radiation from the sun gets blocked by the ___________ layer prism sunburn Bees ozone flower photo under normal light flower photo under UV light

Electromagnetic Radiation (6) X-rays -- used in medicine Ouch!

Electromagnetic Radiation (7) Gamma Rays-- some radioactive substances give it off The last type of radiation is sometimes grouped with gamma rays… (8)_______________Rays -- highest energy radiation; almost all of this radiation from the sun is blocked by the ozone layer and the air. Cosmic Interesting superhero facts: Superman has x-ray vision. The Incredible Hulk was “created” by an accidental overdose of gamma radiation. The Fantastic Four were “created” by cosmic rays.

How Light is Produced When atoms get hit with energy (by _____________ them with electricity or by ____________ them up), the electrons absorb this energy and __________ to a higher energy level. Figure (a) As they immediately fall back down to the “____________ state”, they give off this energy in the form of a particle of ___________ (or other types of electromagnetic radiation) called a _____________. Figure (b) zapping heating jump ground light photon

How Light is Produced Each photon emitted has a specific ___________ (or frequency). The color of the light that is given off depends on how _____ the electron _______ (which depends on how big of a jump it originally made.) The farther the fall, the ___________ energy the photon has. color far fell greater

Figure 11.6: Photons of red and blue light.

How Light is Produced energy Since electrons are located only in certain __________ levels (or orbitals) around the nucleus, only certain specific _________ of light are emitted. Scientists use a _________________ to separate these colors into bands of light. These bands of color look like a ______ code of color which is characteristic of that element. No two elements produce the same ______________ of colors. This can be used to distinguish one element from another contained in a sample. (See Fig. 13.11) color spectroscope bar spectrum

Emission Spectrum Hydrogen Spectrum Neon Spectrum

How hydrogen produces the four visible photons

All the Photons Produced by Hydrogen