Chapter 1, 2, & 3 Flashcards
define enrichment
separation of isotopes
why is fluorine weird?
it only has 1 naturally occurring isotope
what is the Bohr model?
- electrons can occupy DISCRETE energy levels within atom
- can transition b/w these energy levels by ABSORBING or EMITTING EXACTT amounts of energy
define atomic orbital
region of space where there is a high probability of finding an electron
Pauli exclusion principle says . . .
2 electrons can only occupy the same atomic orbital if they have OPPOSITE spins
Aufbau principle says . . .
electrons fill atomic orbitals of lowest energy first - atomic orbitals within a sublevel (e.g. the 3 orbitals in 2p sublevel) are DEGENERATE
exceptions are Cr & Cu
define degenerate
equal energy
which has higher energy, 4s or 3d?
3d
where are electrons removed from first?
4s orbital is further away from the nucleus than 3d so electrons are removed from the furthest shell first
Hunds rule says . . .
electrons fill orbitals in same sub-level singly before pairing up
define wavelength
distance b/w 2 crests in oscillating wave
define frequency
of waves that pass a point in 1 second
order of decreasing wavelength (increasing energy)
radio>microwaves>IR>VIS>UV>X-rays>Gamma
continuous spectrum?
all wavelengths + frequencies of visible light are shown
continuous spectrum?
all wavelengths + frequencies of visible light are shown
line spectrum?
some wavelengths are missing
difference b/w absorption & emission line spectrum
ABSORPTION = ALL COLOURS, black streaks
EMISSION SPECTRUM = BLACK, colorful streaks (black EMU wearing COLORFUL sunglasses)
The longer the arrow in a hydrogen emission spectrum . . .
the greater the amount of energy that is emitted
how does an emission line spectrum form?
- high voltage passed through gas
- electrons become excited
- transition to higher energy levels
- as electrons fall back down to lower energy levels, transitions accompanied by emission of energy in the FORM OF PHOTONS
- the energy released by different elements corresponds to dif wavelengths within the visible light range of EM radiation
Briefly explain how a mass spectrometer works
- used to determine relative atomic masses + organic structure
- sample is vaporised
- bombarded w/ high energy electrons
- produces + ions
- accelerated in electric field
- cations DEFLECTED in magnetic field
- depending on mass / charge ratio
higher mass to charge ratio = ?
LESS DEFLECTION
which is deflected more, 79Br2+ or 91Br+ ?
79Br2+ since it has the LOWER m/z ratio
Solids?
- particles closely packed
- strong forces b/w particles
- vibrate about fixed positions
- fixed shape + volume
Liquids?
- slightly more spread out
- weaker forces b/w particles
- can move past each other
- take shape of container
- fixed volume
Gases?
- particles very spread out
- negligible forces
- no fixed shape / volume
sublimation
from SOLID to gas
e.g. iodine or solid CO2
depostion
from GAS to solid
difference b/w boiling & evaporation?
- BOILING = occurs at specific temp & takes place throughout the liquid
- EVAPORATION = only takes place at surface of liquid and can occur at temp. BELOW the boiling point
mixtures
contain 2 or more substances mixed together
- NOT chemically bonded
- mixed in ANY proportion
- can be separated by PHYSICAL meanss
heterogenous vs homogenous mixture
- homogenous = only 1 phase, uniform composition throughout
- heterogenous = more than 1 phase, non-uniform composition
immiscible
describes 2 liquids that form a heterogenous mixture
define average atomic mass (Ar)
average of the masses of the isotopes in a naturally occurring sample of the element relative to the mass of 1/12 of an atom of C-12