A1 atomic structure Flashcards
what is mass spectrometry?
a machine that measures the masses & abundances of particles.
what is the atomic hydrogen emission spectrum?
- it causes electron movement between energy levels within the atom.
- the spectrum can be used to find the ionisation energy of hydrogen.
what is the relationship between wavelength and frequency?
inverse relationship.
high frequency = low wavelength VERSES low frequency = high wavelength.
why does hydrogen emit light?
- hydrogen’s electron is in the first energy level/ shell.
- if energy/ voltage is supplied in the atom = the electron moves into a higher energy level.
- due to hydrogen electron being UNSTABLE if will jump back down to energy level/ shell one = this emits energy and light.
what is the definition of an orbital?
a region of space in which there is a probability of finding up to 2 electrons e, with opposite spins.
what is the shape of a s orbital?
circle.
what is the shape of a p orbital?
infinity.
what is the order of the orbitals?
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶
what is the Cr and Cu exception when filling electron shells?
has only 1 election in its 4s shell.
how do ions effect the electron configuration?
if 2 + = remove last two electrons (lose 4s before 3d).
if 3 - = add three extra electrons.
what is the charge on hydroxide ions?
OH⁻
what is the charge of sulfate ions?
SO₄²⁻
what is the charge of carbonate ions?
CO₃²⁻
what is the charge of phosphate ions?
PO₄³⁻
what is the charge of ammonium ions?
NH₄⁺
what is the charge of nitrate ions?
NO₃⁻
what is ionic bonding?
ionic bonding is the electrostatic attraction between opposingly charged ions.
what is a giant ionic lattice?
regular grid like arrangement, made of ions, with an uncountable, large and variable number of ions.
what is the conductivity of ions when in a solid state?
- ions fixed in position in the lattice.
- therefore, cannot move.
- no conductivity.
what is the conductivity of ions when in a liquid or aqueous state?
- ions are not in a fixed position, therefore are freely moving.
- ions can move.
- high conductivity.
what two things determine bonding strength in ionic substances?
- size of the ionic charges.
- size of the ionic radius.
how does bonding strength depend of ionic charge?
two ions that have the same radius in both, however one ion has a greater ionic charge. therefore, the attraction between opposingly charged ions in stronger in the ion which has a greater ionic charge.
how does bonding strength depend on ionic radius?
two ions have the same ionic charge, however one ion is a bigger atom, therefore having a bigger ionic radius. therefore, the attraction between the opposingly charged ions is weaker in the bigger atom.
what’s 3 properties of simple molecules?
1) low melting point (MP) and boiling point (BP) = due to weak intermolecular forces.
2) doesn’t conduct electricity = as molecules aren’t charged.
3) some are soluble in water, whereas some are not.
what are dative covalent bonds?
electrostatic attraction between two protons in a nuclei and a shared pair of electrons. both electrons come from the same atom.
what affect does bigger atoms have on the strength of covalent bonds?
bigger atoms = longer bonds = further from nucleus = weaker attraction = bond energy is less and weaker.
what is the structure and properties of graphite?
- 3/4 electrons in the outer shell are used in covalent bonds = the 4th electron is released into a sea of delocalised electrons.
- planar hexagonal layers.
- layers are bonded by weak london forces (IMFs).
- very high MP & BP.
- soft and slippery lubricant due to layers being able to slide over each other.
what is the structure and properties of diamond?
- 4 carbon bonds.
- hard substance = due to 3D structure and strong covalent bonds.
- doesn’t conduct electricity as electrons are held tightly in covalent bonds.
- insoluble.
what is the structure and properties of silicon dioxide?
- contains silicon and oxygen.
- high melting points due to strong covalent bonds having to be broken.
- hard substance = due to 3D structure and strong covalent bonds.
- doesn’t conduct electricity.
- insoluble.
what is the bonding in metals?
electrostatic attraction between positive metal ions and delocalised electrons.
what is the structure of metals?
giant metallic lattice
what 3 things does the strength of metallic bonding depend on?
1) cation charge = the higher the charge, the stronger the bonding.
2) cation radius = the smaller the radius, the stronger the bonding.
3) number of delocalised electrons = the more delocalised electrons, the stronger the bonding.
what is the electrical conductivity like in metals?
HIGH
as delocalised electrons are free to move.
what is the malleability of metals?
VERY malleable as layers of metal ions can slide without disrupting the bond.
what is the name and angle of the shape that two bonds create?
linear
180 degrees
what is the name and angle of the shape that three bonds create?
trigonal planar
120 degrees
what is the name and angle of the shape that four bonds create?
tetrahedral
109.5 degrees
what is the name and angle of the shape that five bonds create?
trigonal bipyramid
90 and 120 degrees
what is the name and angle of the shape that six bonds create?
octahedral
90 degrees
what is the name and angle of the shape that 3 bonds and one lone pair create?
trigonal pyramidal
107 degrees
what is the name and angle of the shape that 2 bonds and 2 lone pairs create?
bent
104.5 degrees
what affect does lone pairs of electrons have in comparison to bonding pairs?
lone pairs repel more
what is electronegativity?
it is the tendency of one atom (of an element ro attract bonding electrons).
why does the electronegativity increase up the group?
- atomic radius decrease.
- less electron shielding (less repulsion in the structure).
- stronger attraction to nucleus.
why does the electronegativity increase across a period?
- similar radiuses and shielding as you go across.
- nuclear charge increases.
- stronger attraction to the nucleus.
what forms polar bonds?
covalent bonds are polar if there is a significant electronegativity difference, between the partial charges, which causes unequal electron pair sharing.
what is a polar molecule?
a molecule is polar if it has asymmetrically arranged polar bonds that don’t cancel out.
how can you experiment if a molecule is polar?
dissolve a substance in a non-polar solvent, and squirt out a jet of liquid, place a charged rod near the jet and if polar it will bend towards rod.
what are london forces?
the attraction between induced dipoles. happens in every molecular substance. very weak due to the little charge in the partial charges.
what does the strength of london forces depend on?
1) number of electrons per molecule = more electrons, means stronger dipoles, meaning stronger attractions.
2) if electrons are roughly the same, consider shape. a linear shape means it is longer and thinner so molecules can pack closer together meaning slightly stronger London forces. a 3d shape means its shorter and fatter so can’t pack as closely together meaning slightly weaker London forces.
what are permanent dipoles?
when one molecules are polar due to one atom being more electronegative so they attract like London forces but stronger as dipoles are already there.
what is hydrogen bonding?
the attraction between H+ in O-H/N-H/F-H and lone pairs on :O/:N/:F.
strongest IMF.
how to tell if substances mix?
they mix if new IMFs are similar/stronger than the broken IMFs.
what are the rules of thumb regarding miscibility?
1) to mix with water you must be making hydrogen bonds.
2) to mix with non-polar substances you need to be also non-polar.
