Chem 17 Reviewer (1st Exam)
CHEMISTRY 17 1ST LONG EXAM REVIEWER I. ELECTRONIC STRUCTURE OF ATOMS
-arrangement of atoms’ electrons
-the number of electrons in an atom
-distribution of electrons around the nucleus and their energies
• ATOMS *Billiard Ball Model (JOHN DALTON) *Plum Pudding Model (JOSEPH J. THOMPSON)
*RUTHERFORD’s Model of Atom
-atoms are tiny, hard, indivisible spheres
-electrons (negative charge) occupy the atom
- Atom is mostly empty space with a dense nucleus
• PROBLEMS with Rutherford’s Model *According to laws of physics, Rutherford’s atom should collapse
*The model CANNOT explain differences in properties of elements
*The model CANNOT explain the colors emitted by elements when heated A. THE QUANTUM MODELS (WAVE)
-formed through studies about light
• DESCRIBING ELECTROMAGNETIC WAVE
*Wavelength (λ”lambda”) -distance between two adjacent peaks or troughs (m)
*Frequency (ѵ ”nu”) - number of cycles(complete wavelengths) that pass a given point each second (Hz or /s)
**Wavelength is inversely proportional to frequency. Where: ↔ c= 3.00 x 10⁸m/s
B. QUANTIZED ENERGY AND PHOTONS
• Blackbody Radiation o Perfect absorber and emitter of light o At high temperature, solids emit radiation o Radiation depends on the temperature not in the element the solid is made from. o PREDICTION: “As temperature increases, the frequency of light emitted also increases.” o OBSERVATION: There was a peak.
• Photoelectric Effect and Photons o When a beam of light shines on a certain surface (e.g. some metals), electrons are ejected. o The effect is instantaneous. o PREDICTION: ”It will take time for effect to be observed”; “and light will produce the effect, given enough time” o OBSERVATION: Effect is instantaneous. There is a minimum frequency of light needed to produce the effect. o **”If frequency of light is below a certain value called the threshold frequency, the
-arrangement of atoms’ electrons
-the number of electrons in an atom
-distribution of electrons around the nucleus and their energies
• ATOMS *Billiard Ball Model (JOHN DALTON) *Plum Pudding Model (JOSEPH J. THOMPSON)
*RUTHERFORD’s Model of Atom
-atoms are tiny, hard, indivisible spheres
-electrons (negative charge) occupy the atom
- Atom is mostly empty space with a dense nucleus
• PROBLEMS with Rutherford’s Model *According to laws of physics, Rutherford’s atom should collapse
*The model CANNOT explain differences in properties of elements
*The model CANNOT explain the colors emitted by elements when heated A. THE QUANTUM MODELS (WAVE)
-formed through studies about light
• DESCRIBING ELECTROMAGNETIC WAVE
*Wavelength (λ”lambda”) -distance between two adjacent peaks or troughs (m)
*Frequency (ѵ ”nu”) - number of cycles(complete wavelengths) that pass a given point each second (Hz or /s)
**Wavelength is inversely proportional to frequency. Where: ↔ c= 3.00 x 10⁸m/s
B. QUANTIZED ENERGY AND PHOTONS
• Blackbody Radiation o Perfect absorber and emitter of light o At high temperature, solids emit radiation o Radiation depends on the temperature not in the element the solid is made from. o PREDICTION: “As temperature increases, the frequency of light emitted also increases.” o OBSERVATION: There was a peak.
• Photoelectric Effect and Photons o When a beam of light shines on a certain surface (e.g. some metals), electrons are ejected. o The effect is instantaneous. o PREDICTION: ”It will take time for effect to be observed”; “and light will produce the effect, given enough time” o OBSERVATION: Effect is instantaneous. There is a minimum frequency of light needed to produce the effect. o **”If frequency of light is below a certain value called the threshold frequency, the