Atomic Structure

Electromagnetic Radiation Energy traveling through space c = λ* ν Wavelength – (λ) distance between 2 peaks or troughs on a wave – Units: m, cm, nm Frequency – (ν) # waves that pass a point in time – Units: Hertz (Hz) or /s Speed of light – (c) = 3.0*10 8 m/s

Energy of photons

Spectrums See light patterns Electromagnetic Spectrum – shows all types of electromagnetic radiation Diffraction – light is separated (see colors of rainbow from white light) – See dark and light spots Continuous spectrum – see ranges or bands of color Line spectrum – see only specific wavelengths (looks like lines of color) – Changes in energy emit certain colors

Bohr Model of Atom Primarily dealt with Hydrogen atom Also called Planetary Model electrons orbit the nucleus like the planets orbit the sun Electrons reside in specific energy levels – Lowest possible state = ground state (level 1) – Higher states = excited states – Absorb energy to go to excited state; emits light/energy when comes back down

Quantum Mechanical Model of Atom Quantum Mechanics – deBroglie, Schrodinger, Heisenberg Electrons not just particles – also act as waves Find electrons in orbitals – know probable location of electron but not exact at any given time (Heisenberg Uncertainty Principle) Schrodinger assigned quantum numbers to describe properties of electrons – Principal quantum number (n) = main energy level/shell (n=1,2,3,….) – Angular momentum quantum number (l) = shape = block/subshell (s=0; p=1; d=2; f=3) – Magnetic quantum number (m l ) = orientation (-l to +l) – Spin quantum number (m s ) = +1/2 or -1/2

Orbital Shapes s orbital = sphere - only 1 orientation (s) have nodes – areas of high probability and 0 probability p orbital = dumbbell shape – 3 possible 2 lobes oriented about x,y,z axes (p x, p y, p z ) d orbital = double dumbbell – 5 possible 4 lobes oriented about x,y,z axes (d xy, d yz, d xz, d x2y2, d z2 ) f orbital = 3 dumbells – 7 possible 6 lobes oriented about x,y,z axes (f xyz, etc)

Pauli Exclusion Principle = no 2 electrons can have the same set of quantum numbers Example: Sulfur Identify Group, Period, block, total # e- Write orbital notation/orbital diagrams to see specific quantum numbers for atoms/electrons lines/boxes with arrows (2 opposite arrows on each line) (Aufbau Principle = building up)

Electron configuration – Show all electrons in the atom Noble Gas notation – Short hand – bracket off number electrons equal to previous Noble gas Remember d orbitals – 1 less than the period they are in (3d in period 4); and f orbitals – 2 less than the period they are in (4f in period 6)

Periodic Table Arranged according to increasing atomic number Grouped according to similar properties or characteristics Periodic Trends: – Ionization energy – Electron affinity – Atomic radius – Metallic character