Gchem exam 1 Flashcards

Terms Definitions
Photoelectric Effect
When electromagnetic radiation of sufficient minimum energy strikes the surface of a metal inside an evacuates tube, electrons are stripped off the metal to create an electric current.
Emission spectrum
Bright line spectrum
Absorption spectrum
Wavelengths absorbed
High frequency = shorter wavelengths=blue.
Low frequency = longer wavelengths = red
Quantum Mechanics
Based on the wave properties of matter, describes the behavior of very small particles much better.
Heisenberg uncertainty principle
Theoretical association that is consistent with all experimental observations
It is impossible to determine accurately both the momentum and the position of an electron simultaneously
Atomic orbitals
In any atom, all orbitals with the same principal quantum number n are similar in size. In an atom, larger values of n correspond to larger orbital size. Each orbital with a given n value becomes smaller as nuclear charge increases
Alpha particle
A helium ion with a 2+ charge; an assembly of two protons and two neutrons
Canal ray
A stream of positively charged particles that moves toward the negative electrode in a cathode ray tube; observes to pass through canals in the negative electrode.
Continuous spectrum
A spectrum that contains all wavelengths in a specified region of the electromagnetic spectrum.
Electromagnetic radiation
Energy that is propagated by means of electric and magnetic fields that oscillate in directions perpendicular to the direction of travel of the energy
Emission spectrum
The spectrum associated with emission of electromagnetic radiation by atoms resulting from electron transitions from higher to lower energy states
Mass spectrometer
An instrument that measures the charge to mass ratio of charged particles
A packet of light or electromagnetic radiation
Spectral line
Any of a number of lines corresponding to definite wave lengths of electromagnetic spectrum
(.2 ✖ 5) (.5 ✖2) (.3 ✖3 ) (.7✖4)
Transition elements..
Are in transition from base to acid
Atomic Radius
Increases from top to bottom and decreases from left to right
Rule of elements
All elements are neutral
Ionization Energy
2nd IE > 1IE because its easier to remove an e- from neutral than from a positive nucleus (ion)
Ionization energy
Amount of energy required to remove an electron
Electron affinity
Amount of energy needed to accept an electron
Metals lose electrons
Gain electrons thus ion is larger than element
Species that have the same number of electrons
-only applies to covalent. When the change in EN > or = to .6 it is polar covalent
Electronegativity trend
Decreases from top to bottom and increases from left to right
EN example
C : F F > EN than C so C :F where F is slightly negative and C is slightly positive
Properties of Metals
High electrical conductivity that decreases with increasing temp. / high thermal conductivity/ metallic gray or silver luster / almost all are solids/ malleable / ductile/ outer Shells contain few electrons/ form cations/ form ionic compounds wIth nonmetals/ solid state characterized by metallic bonding
Properties of Nonmetals
Poor electrical conductivity/ good heat insulators/ no metallic luster/ solids, liquids, gases/ brittle in solid state/ no ductile/ outer shells contain four or more electrons/ form anions by gaining electrons/ form ionic compounds with nonmetals:/ covalently bonded molecules
Group 7A / salt formers
Group 1A
Form Cations, alkali metals
Group 2A
Form +2 cations , alkaline earth metals
Mass Spectometry
Light is deflected more than heavy.
Mass Spectrometry
Magnitude of the accelerating voltage (electrical field strength). - higher voltages result in beams of more rapidly moving particles that are deflected less than the beams of the more slowly moving particles produced by lower voltages.
Mass Spectometry
Magnetic Field Strength. - Stronger fields deflect a given beam more than weaker fields.
Mass Spectrometry
Masses of the particles. - because if their inertia, heavier particles are deflected less than lighter particles that carry the same charge.
Mass spectrometry
Charges on the particles. - particles with higher charges interact more strongly with magnetic fields and are this deflected more than particles of equal mass with smaller charges
Properties of elements are directly related to atomic number.
Rutherford scattering experiment
Conclusion: some particles are deflected considerably, a few alpha particles collide head in with nuclei and deflected back toward the source, but most alpha particles pass straight through or are deflected very little because of the electron cloud.
Atom models
1st- Thompson ( plum pudding model) 2nd - Bohr (orbital model) 3rd -schrodinger ( waves)
Electrical charge
Specific Heat problem
Amount of heat = mass(g) ✖specific heat(j/g•C) ✖temp change ( Celsius) Specific heat = 4.18 j/ g•C K= c + 273F =1.8C + 32
Specific gravity
Is equal to density
2.54 cm = 1 in. 1L = 1.057 qt. 454g= 1lb. 1km=1000m. 1cm= .01m. 1mm= .001m.
Law of definite proportions
Different samples of any pure compound contain the same elements in the same proportions by mass
Extensive property
A property that depends on the amount of material in a sample
Intensive property
A property that is independent of the amount of material in a sample
Law of conservation and energy
The combined amount of matter and energy in the universe is fixed
Eugene Goldstein
Discovered proton through canal rays
Distance between crest and trough
Symbol is nu. (V) number of wave crests passing a given point per unit time
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