CHEM 111 Exam #2 9/18/13 7.3: The Wave Particle Duality of Matter and Energy - de Broglie Wavelength - if energy/light can behave as particle and waves, why can’t matter behave as waves and particles o waves not allowed to equal n=3⅓-λ=hmu the objects mass is inversely proportional to its wavelength o U = speed o h = plancks constant o m = mass-p=hλ Momentum is inversely proportional to wavelength - Heisenberg’s Uncertainty Principle: Δx∙mΔu ≥ h/4πo x is position; u is speek9/18/13 7.4: The Quantum Mechanical Model of the Atom - According to Heisenberg, we cannot know both the momentum and the position of a particle.- Schrodingers equation: HΨ = EΨ- Quantum numbers and energy levels o • Level (n) – also referred to as shellso • Sublevel (l) – also referred to as subshellso l = 0 is an s sublevel → can hold 2 electrons (1 orbital) o l = 1 is a p sublevel → can hold 6 electrons (3 orbitals) o l = 2 is a d sublevel → can hold 10 electrons (5 orbitals)o l = 3 is an f sublevel → can hold 14 electrons (7 orbitals) o Orbital – each n, l, and ml defines shape, size, energy, and orientationof an orbital.9/23/13 8.1 Characteristics of many electron Atoms - The Pauli Exclusion Principleo No two electrons in the same atom can have the same four quantumnumberso Therefore an atomic orbital can hold a maximum of 2 electrons and they must have opposing spins.- Components that results into the splitting of levels into sublevels o Nuclear charge: attraction from the nucleus and electronso Shielding: electrons shield one another from the attraction of the nucleus o Penetration: based on the shrodinger equation, the 2s sublevel is more stable than the 2p because it penetrates closer to nucleus 9/25/13 8.2 The Quantum- ‐ Mechanical Model and the Periodic Table - Which orbital has the lowest energy? → 4s- Aufbau Principle – Start at the lowest energysublevel available and work up- Energy in increases with more orbitals - Depends on the Z # or the top atomic #- Cu and Cr are the ones that do not follow the trend- If the diagram above end with an up arrow then it is (+1/2)and if it goes down then (-1/2) 9/27/13 8.3 Trends in Three Atomic Properties - ↓← atomic radius 9/30/13 8.3 Trends in Three Atomic Properties - How many electrons can occupy and 3d orbital? → 2 in one orbital- [Ar]4s23d104p3 is the electron configura8on of a(n) atom? → As- Categories of Electrons: o Inner (core) electrons – electrons in completed shellso Outer electrons – those in the highest energy level (highest nvalue)o Valence electrons – those involved in forming compoundso – For main group these are the outer electronso – For transition elements it is the ns electrons and (n-1) d electrons- Anion ( -); Cation (+) - ↑→ Ionization energy – increases across a period and decreases down a group- ↑→ Electron affinity – goes not include far right side (exception) 10/2/13 8.4 Properties of Monoatomic Ions (pg 317-322) - Isoelectronic – when two or more elements or ions have the same electron configuration- Determine the ion charge for an element and then looking at how much more is needed tofill the shell and have 8 total electrons - Diamagnetic – is not attracted and is slightly repelled by an electromagnetic field- Paramagnetic – is attracted to an electromagnetic field.10/4/13 2.7 and 9.1 Compounds: Intro to Bonding - Transferring electrons from one element to another forms ionic compounds- Sharing electrons between atoms of different elements forms covalent compounds- Binary ionic compounds – compounds made up of an anion and a cation.- Attraction increases as charge increases- Attraction increases as size decreases- Lewis electron-dot symbols – using dots around the atomic symbol to represent the valence electrons for that atom or ion.- Octet Rule – when atoms bond, they lose, gain, or share electrons to attain a filled outer level of 8 electrons (except….)2/24/14 8.2, 8.3 The Periodic Table and Trends iCLICKER #33• What is the best electron configuration for a neutral titanium atom (atomic number = 22)?o [Ar]4s2 3d2• What is the best electron configuration for a neutral vanadium atom (atomic number = 23)?o [Ar]4s2 3d3o (Ar)3d3 4s2 → also right as it is written by increasing energy Period 4:• ns orbital fills before (n–1)d orbital, thus:o Potassium: 19 electrons [Ar]4s1 o Calcium: 20 electrons [Ar]4s2Exceptions• Half-filled orbitals are unexpectedly stable:• Chromium: 24 electrons → Condensed electron configuration: [Ar]4s1 3d5• Copper: 29 electrons → Condensed electron configuration: [Ar]4s13d10Categories of Electrons• Outer electronso find highest n value; EX: Chromium = 4 EX: Cr → (Ar) 4s1 3d5 → only 1 outer electron EX: (He) 2s2 sp3 → highest n value = 2, 5 outer electrons o any electron in one of these orbitals is an outer electrono (using the #A column labels, the column number is number of outer electrons) Groups all have the same number of electrons• Inner electronso non-outer electrons; for non-transition metalso any electrons in common with the previous noble gas and filled (completed) d or f orbitals in the transition series EX: (Ar) 4s1 3d5 → for chromium (Ar) is the inner electrons, 4s1 is the outer electrons  EX: Cu: (Ar) 4s1 3d10 → (Ar) is the inner, 4s1 is outer and 3d10 is inner• Valence electrons• ▫ for non-transition elements: outer electrons are• valence electrons• ▫ for transition elements: outer ns electrons and• (n–1)d electrons• 112/26/14 8.3, 8.4: Periodic Trends and Ions Trends in Atomic Size • As quantum number n increases (period #) …. Size increases • As Zeff increases… size decreases • For transition elements ( d-block) and inner transition elements (f-block) o Not much variation in size due to shielding by orbitals Ionization Energy • Ionization energy: is the energy required for complete removal of an electrono n= ∞ → electron removed  n→ n = ∞Ionization forms Ions• Atom + Energy → Ion+ + electron– (cation, + charged atom) (anion, - charged atom) o More protons than electrons • 1st Ionization Energy (IE1)o removes highest energy electron in the atom (neutral) • 2nd Ionization Energy (IE2)o removes highest energy electron in the ion (positive) o always larger energy, especially if it’s an inner electronIsoelectronic: same number of electrons