CH1.1 Formulae and equations + CH1.2 Basic ideas about atoms Flashcards
oxidation number
is the number of electrons that need to be added to (or taken away from) and element to mae it neutral
which elements exsist as diatomic elements
Iodine, Bromine, Chlorine, Fluorine, Oxygen, Nitrogen, Hydrogen
In Brave Circomstance Flamingos Overcome Natural Histerics
elements
substance which can not be split inot anything simpler by chemical means
atom
smallest part in a element that can tak part in a reaction
molecules
combination of 2 or more elements
ion
electrically cahrged atom or molecule
a positive ion is called a …
a negative ion is called a …
cation
anion
valency
a numerical measure of the combination power of an atom/ion
meaning of OILRIG
Oxidation is loss (of electrons) Reduction Is Gain (of electrons)
standard oxidation state of hydrogen
+1
standard oxidation state of oxygen
-2
standard oxidation state of fluorine
-1
when is the oxidation state of hydrogen not the standard value and what is the new value
-1 in hydride ions (NaH-)
when is the oxidation state of oxygen not the standard value and what is the new value
-1 in hydrogen peroxide H2O2
+2 in F2O
realtive atomic mass
the mass of an atom relative to the carbon-12 isotope having a value of 12
isotope
atoms with the same atomic number but different mass number
mass spec peacks give what and the peak intensity gives what
the atomic mass and the intensity gives the realtive abundance
what is relevent to know when caluclating thigns to do with the mass spec
the largest abundance is scaled up to 100% and everything else is scalled arcordingly
orbital
a region in space where on is likely to find an electron, each can hold up to 2 electrons with opposite spin
ionisation energy
measure of the amount of energy required to remove electrons from an atom
what is ionisation energy effected by
distance from nucleus
effetive nuclear charge of atom
1st ionisation energy
the energy required to remove 1 mole of electrons from one mole of isolated gaseous atoms to orm 1 mole of gaseous positive ions
redox
when reduction and oxidation takes place within a reaction
oxidation
removal of electrons
reduction
gain of electrons
rules of solubility (allways soluble)
NAG SAG
Nitrates (NO3-)
Acetates (C2H3O2-)
Group 1 (Li+..)
Sulfates (So4 2-)
Ammonium (NH4+)
Group 7 (F- …)
Exceptions to the solubility rules (Never soluble together)
PMS (never souble with sulfates and group7)
Pb (lead), Mercury (Hg), Silver (Ag)
CaStro Bear (never soluble with group 7) Ca(2+) Sr (+2) Ba (+2)
atomic number =
number of protons
mass number =
protons + neutrons
why do things become Radiacativity
because the neutron proton ratio is to big to keep the atom stable
alpha particle emission
2 neutrons and 2 protons (-4 from today -2 thebottom number)
Beta particel emission
fast moving electron (+1 to atomic number)
gamma particle emission
high energy electromagnetic radiation (no charnge to numbers of elements)
positron
positive electron, antiparticle of a electron, decay of a proton into a neutron and a electron
electron capture
electron from inner energy level captured by neuleus. combines with a proton and makes a neutron
alpha beta and gamma in a magnetic field
alpha - deflected
beta - defelcted
gamma - no deflection
alpha beta and gamma in electric field
alpha attracted to -iv plate
beta attracted to +iv plate
gamma no effect
what is alpha stoped by
piece of paper
what is beta stopped by
0.5 cm of metal
what is gamma stopped by
2cm of lead
half life
time taken for half the atom in a radioscope to decay
radioactive isositive used in medicine (2) and what for
cobalt-60 : in radiotherapy for cancer. (gamma)
Technetium-99m : medical radioistope
what is used in food and what does it do (radioactive)
gamma is used to kill microbes in food
carbon dating two examples
carbon-12 ; used to calculate the age of plants and animals remains.
potassium-40 : used to estimate the geological age of rocks.
what is a non medical industrial use of radioactive isotope
measuring the thickness of metals
factors effecting the energy of an electron in an atom
screening
attraction by the nucleus, greater force if…
-nuclear charge is greate
-distance of electron from nucleus is less
ionsisation energies
how much energy it takes to remove the weakest held electron from a atom i its gaseous state
what have ionisation energy’s given evidence of
sub levels and electron levels
successive ionisation energies
meaures of the enrgy required to remove each electron untill all have been removed from a atom
two equations needed when looking at emission and absorbstion spectrum
c=f(wavelength)
E=hf
h= planck’s constant
c= speed
f=frequency
E=energy
absorption spectra
dark lines on bright background
absorption spectrum exsplaines
Electrons move from lower to higher energy lever due to a white light shined through vapour of an element, certain wavelengths will be absorbed by the atom and removed from the lightlooking though the spectrometer, black lines will appear on the spectrum where light of some wavelengths has been absorbed.
emission spectrum colours
number of coloured lines on a black background
emission spectrum exsplained
atoms are given energy by heating or by an electric field.
electrons are excited and the additional energy promotes them up a energy level. When the source of energy is removed the electrons falls back down a energy level relasing a photon of energy.
The photon has a certain frequency
what section of electromagnetic spectum is balmer series found
visible ligh
what part of the electromagnetic spectrum is pachen
infared
what section of the electromagnetic sectrum is lyman found
ultra violet
link all the the hydrogen spectrum and electromagnetic series
Paschen - infared
Balmer - Visible light
Lyman - Ultra violet
wich spectrum is due to electrons returning to the sub shell’s respectively n=1 , n=2 and n=3
Lyman
Balmer
paschen
hydrgoen spectrum exsplained
frequency lines get closer together as you go higher, this is untill they converge to a limit this is the poit where the energy is no longer quantum. the atom has becomed ionised
