Elements Of Life (EL) Flashcards
mass number
atomic number + no. neutrons
isotope
atoms of the same element but different mass number
relative atomic mass
average of the relative isotopic masses
mass spectrometry
measures the atomic or molecular mass of particles sample and the relative abundance of different isotopes in an element
nuclear fusion
two light atomic nuclei fuse together forming single heavier nucleus of new element and releasing energy
spectroscopy
study of how light and matter interact
wavelength =
speed of light / frequency
particle theory of light
light is a stream of tiny packets of energy called photons
energy of photon =
planck constant x frequency
Bohr’s theory main points
electron in hydrogen atom exists only in certain definite energy levels, a photon of light is emitted/absorbed when electron changes energy level, energy of photon is equal to difference between two energy levels
describe n=1 to n=4 shells
n=1 2 electrons
n=2 8 electrons
n=3 18 electrons
n=4 32 electrons
describe the sub shells
s=2
p=6
d=10
f=14
atomic orbitals
sub shells are divided into orbitals
s = 1 s orbital
p = 3 p orbitals
d = 5 d orbitals
f = 7 f orbitals
periodicity
patterns or trends in physical properties within groups
dative covalent bond
both bonding electrons come from the same atom
bond angle for 4 single covalent bonds
109.5
bond angle for 3 single covalent bonds + lone pair of electrons
107
bond angle for 2 single covalent bonds + 2 lone pairs of electrons
104.5
linear bond angle
180
planar bond angle
120 (three groups of electrons)
bipyramidal bond angles
120 to 90 depending on position in molecule (5 groups of electrons)
relative atomic mass
mass of the atom relative to carbon-12, no units
molar mass
mass of one mole
amount in moles (n) =
mass (m) / molar mass (M)
relative formula mass
sum of the relative atomic masses of the elements making it up
Avogadro constant
6.02x10(23) mol. number of formula unitise one mole of a substance.
Difference between molecular and empirical formula
molecular - actual numbers of different types of atom
empirical - simplest ratio for the moles of atoms
percentage yield =
(experimental yield / theoretical yield) x 100
first ionisation enthalpy
energy required to pull an electron out of an atom
X -> X+ +e-
explaining change in thermal stability as group goes down group 1+2
cations with higher charge density can polarise negative charge cloud around the carbonate ion making it less stable and easier to break up on heating
alkali
base that dissolves in water to produce HO- ions
concentration in (mol/dm3) =
concentration (g/dm3) / molar mass (g/mol)
