Unit Two – Chemistry Flashcard

 

 

Atom

 

Smallest partical of an element

 

 

Democritus

  • Atoms are indivisible and indistructable
  • No experiments. Noe scientific method.

 

 

Dalton

  • Developed the Atomic theory
  • Believed that a few kinds of atoms made up all matter
  • Elements are composed of only one kind of atom; and compounds made from two or more atoms

 

 

Thompson

  • Studied the cthode ray tube-made of particles that were negativley charged called them electrons
  • Made the plum-pudding model – said that electrons were embeded on a postivley charged ball of matter

 

 

Rutherford

  • Preformed the gold foil experiment (disproved plum pudding model)
  • Said that atoms are mostly empty space

 

 

Bohr

  • Electrons can olnly be certain distances away from nucleus (distance corresponds with energy level)
  • Farthest away highest energy
  • Closest, lowest energy

 

 

 

Quantum

The difference between energy levels

 

 

Chadwick

  • Said Rutherford only accounted for only half the mass of the nucleus
  • Proved the presence of nuetrons in the nucleus

 

 

Milikan

Proved the charge to mass ratio of an electron

 

 

Electron

  • Negative charge
  • Orbit around nucleus
  • Mass so low its neglected

 

 

Proton

  • Positivley charged
  • located in nucleus
  • mass = 1 amu

 

 

Nuetron

  • Neutrally charged
  • Located in nucleus
  • mass = 1 amu

 

 

Empty Space Concept

  • The space around the nucleus is empty
  • Electrons orbit in this space

 

 

Nucleus

  • Central portion of an atom
  • made of protons and neutrons

 

 

Atomic Number

  • The number of protons

 

 

 

Isotopes

  • elements with the same atomic number but different mass
  • Atomic mass is the isotopes averaged

 

 

Ground State

  • Electrons at the lowest energy level
  • Closest to nucleus

 

 

Excited State

  • Highest energy level
  • Unstable condition
  • have absorbed heat

 

 

Dual Nature of Light

  • Frequency and wavelength are inversley related
  • Frequency increases, wavelength decreases

 

 

Particle Nature

  • Shine light on matter it will conduct heat
  • Electrons DO move

 

 

Photons

  • Packets of energy
  • behave like particles

 

 

Frequency

  • Cycles per second

 

 

Amplitude

  • Bright or intense amount of light

 

 

Continuous Spectra

  • Wavelengths (colors) Fade from one to another across the complete spectra

 

 

Bright Line Spectra

  • Spectrum that only contains certain wavelengths

 

 

When light strikes and electron

  • electron moves to higher energy level then goes back down
  • This creates bright line spectra

 

 

Quanta

  • The amount of energy required to excite an electron to the highest energy level

 

 

 

Heisenburg’s Uncertainty Principle

Stated that the more precisley the momentom of a particle is known the less precisley the postion is known at a given time

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Orbital

A region of space around the nucleus of an atom where an electron is found

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Principle Quantum Number

  • Each principle energy level consists of one or more sublevels
  • n = main energy level (1,2,3,4)

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Sublevel

  • Can have one or more
  • S, P, D, F

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Valence Electrons

  • All electrons in the outermost energy level

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Kernal

  • The nucleus and all non-valence electrons

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Electron Configurations

  • 3D orbital is higher than 4S

1s; 2s; 2p; 3s; 3p; 3d; 4s; 3d; 4p…

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Ion

  • An atom that has gained or lost an electron
  • Atom is no longer nuetral

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Anion

  • negative ion
  • Atom has gained and electron

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Cation

  • Postive Ion
  • Atom has lost and electron

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Electron Dot Notation

  • The symbol and dots that show the type of atom and the valence electrons

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Ionic Radius

  • The measure of the size of the atoms ion in a crystal lattace

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Ionization Energy

  • The energy required to remove the most loosely held electron from an atom

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Electron Affinity

  • The energy change that occurs when an atom gains an electron

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Electronegravity

  • A property of an element that indicates how strongly an atom attracts electrons (chemical bond)

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