chemistry chapter 3 and 4 Flashcards
john dalton
featureless sphere billiard ball
jj thompson
plum pudding model discovered electrons cathode ray tube
ernest rutherford
discovered small pos nucleus gold foil atoms are mostly empty space
james chadwick
found neutrons
isotopes
same number of protons and different number of neutrons
radioisotopes
unstable emit gamma rays and alpha or beta particle
light
electromagnetic radiation measured in wavelengths
photoelectric effect
electrically charged particles are released from or within a material when it absorbs electromagnetic radiation
max plank
heated blackbodies found a quantium of energy and he found that light has similar properties to particle
einstein
explained the photoelectric effect and said that photons are a unit of light energy
what was the issue with rutherfords model
rutherfordss model was incorrect becase if that was true the negative electrons wouldve creased kinto the positivve nucleus
neils bohr
viewed hydrogen through a spectroscope saw bright coloured lines and proposed that electrons were moving at fixed distances from the nuclesu bohrs model only worked for hydrogen
schrodinger
developed a wave equationthat could calculate electron energy levels electrons were now described as existing in a 3D space called an orbital
heinsenberg
he came up with the uncertainty principle because if you try and find where an electron is it chnages its position we can only describe the probability of where an electron is
orbitals vs orbits
ORBITALS quantum mechanics 2e- 3D distance from nucleus varys no set path
ORBITS bohr 2ne- 2D distance from nucleus is fixed path is elliptical or circular
what is the principle quantum number
(n) corresponds to the energy level (shell) it is a whole # 1 2 3
what is the secondary quantum number
(l) describes the shape (s,p,d,and f) subshells in n=1 only s orbitals exist, in n=2 there can only be s and p orbitalsin n=3 there can be s p and d and in n=4 there can be spd adn f orbitals
the magnetic quantum number
(Mi) describes the orientation of the orbital ranges from +l to -l s orbitals (l=0)ml can only be 0 p orbitals (I=l) ml can be +1 0 -1 d orbitals (l=2) ml can be +2 +1 0 -1 -2 f orbitals (l=3) ml can be +3 +2 +1 0 -1 -2 -3
the spin quantum number
(ms) relates to the spin of the e- tow electrons pared withitn the same orbital lmust have opposite spins (pauli exclusion principle) must be either +1l2 or -1l2
the aufbau principle
e must fill orbitals in order of increasing energy starting form nearest to the nucleus
pauli exclusion principle
two electrons paired within the same energy level must have opposite spins
hunds rule
you must half fill each orbital w parallel spins before pairing electrons with opposite spins
ferrromagnetism
very strong magnetism exhibited by materials that contain nickel, iron, cobalt they have several unpaired e-
paramagnetism
weak attraction of a substance to a magnet for individual atoms such as aluminium and platinum due to their unpaired e- all having the same spin which generates a weak magnetic feild
laser
e- are stimulated to higher energy states then release radiation when they return to ground state this release of photons trigger other atoms to do the saem increasing the intensity of the light mirrors are used to reflect causing them to collide with atoms and release more photons
light amplification by simulated emission of radiation
they produce an intense beam of light in a single wavelength the waves are parallel and coherent can transfer a great deal of energy causing burns and blindness
MRI
magnetic resonance imaging uses a strong magnetic fe3ild to cause magnetic fields of hydrogen atoms in the human body to align in the same direction and radio waves are then applied and cause the magnetic fields to flip int the opposite direction a scanner detects these changes and a computer converts them into a 3D image soft tissues including muscles organs and the brain can be seen.
xray
involve electrons being acceletated to high velocities adn collide with a terget material such as tungsten casuign its elecyrons to also jump to a higher energy level when the electrons return to their ground state very high energy photons called xrays are emitted bones absorb x rays producing a shadow image on the film
ionic bond
an electrostatic attraction between oppositely charged ions (metals lose electrons to form positive ions nonmetals gain electrons to form negative ions)
these attractions form a crystal lattice structure made of several oppositely charged ions the smalled ration represented by the chemical formula
covalent bonding
when two nonmetals share electrons the shared pair of electrons forms a covalent (intermolecular bond the bond forms at an optimal distance to minimize their energy and minimize their repulsion
