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Flashcards do conjunto (25)
- 1what is used to observe atoms?scanning tunneling microscope
- 2electron cloudgives the atom it's volume
- 3neucleusgives the atom it's mass
- 4atomic numbernumber of protons (electrons) in an element
- 5mass number-total number of protons + neutrons
-the atomic mass is rounded to the nearest whole number to get the atomic number
- 6isotopesatoms that have the same number of protons but different number of neutrons
- 7ground statethe lowest energy state possible where electrons usually are in atoms
- 8excited statewhen electrons gain energy, they enter the excited state, a higher energy state
- 9energy level-region around the nucleus where an electron is likely moving
-electrons can move from one energy level to another - 10quantum of energyamount of energy required to move an electron from one energy level to another
- 11principle quantum number-(n)
-describes energy level of an electron in an atom
-n=1-7
-as n increases, so does the distance from the nucleus and the energy of the electron - 12orbital quantum number-(L)
-tells the shape of the orbital
-3D region where electrons are likely to be found - 13magnetic quantum number-(m1)
-describes the orientation of the orbital in space (x, y, z axis)
-s orbital : 1 orientation
-p orbital : 3 orientations
-d orbital : 5 orientations
-f orbital : 7 orientations - 14spin quantum number-(ms)
-describes the spin of an electron
-ms = +1/2 and -1/2
-electrons spin clockwise and counterclockwise - 15amplitudethe height of a wave from origin to crest
- 16wavelengththe distance between waves
- 17frequencythe number of waves that pass a certain point in an amountof time
- 18Democritus-4th century BC
-suggested matter was composed of atoms
-atom was indivisible and indestructible
-theory was not based on scientific method - 19John DaltonAtomic Theory
1) all elements are comp. of atoms
2) atoms of same element are identical, and different from other elements
3) atoms of diff. elements can physically mix or chemically combine to form compounds
4) chem. reactions occur when atoms are seperated, joined or rearranged and their atoms can't change into atoms of a diff. element - 20J.J. Thompson-discovered electron
-used cathode ray tube
-atoms contained negative particles (electrons)
-atoms are neutral, so must be + particles
-atoms are divisible into subatomic particles
-"Plum Pudding Model" - 21Cathode Ray Tube-attracted to positive plate
-opposite charges attract, like charges repel
-cathode ray= negatively charged particles - 22Ernst Rutherford-Gold Foil experiment
-led to discovery of nucleus
-most of positive particles passed through foil
-a few particles hit the nucleus and bounced back - 23Gold Foil experimentResults
-99% of alpha particles (+) went thru
-1% were deflected at angles
-a few totally reversed directions
Conclusions
-atom is mostly empty space
-nucleus is +, small and dense
-elecrons are so small, didn't interfere with alpha particles - 24Neil Bohr-"Planetary model" of atom
-electrons are arranged in specific circular paths (or orbits) around the nucleus, different paths have differnet energy levels - 25Erwin Shrodinger-developed model based on mathematical equations like the quantum mechanical model
-model suggest where electrons probably are outside nucleus
-electrons don't travel on set path
-electrons have a specific amount of energy
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- FlashCards sobre Sem título, criado por cbyers em 14-10-2015.
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