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What are the 5 steps of a mass spec?
vaporisation, ionisation, acceleration (elec), deflection (mag), detection
What is the definition of ionisation energy?
the energy required to remove one mole of gaseous electrons from one mole of gaseous atoms, forming one mole of gaseous ions
what is the RAM
the weighted mean mass of an atom of an element compared to 1/12 the mass of C-12
what is the RIM
mass of an atom of an isotope compared to 1/12 the mass of C-12
what is the mass of an electron
1/1840
what and why are the IE trends across the period
IE increases
nuclear charge increases
radius decreases
shielding stays constant
what and why are IE trends down the group
IE decreases
shielding increases (more shells)
radius increases
outweighs charge increase
What is the electron config of O
1s2 2s2 2p6 3s2 3p4
Electron config of Cr (24)
1s2 2s2 2p6 3s2 3p6 4s1 3d5
Electron config of Cu (29)
1s2 2s2 2p6 3s2 3p6 4s1 3d10
What is an orbital
a region within an atom that can hold up to two electrons with opposite spin. It’s a region in space with a high probability of finding an electron
What happens to IE between Be (4) and B (5)
decreases - Be has 5th electron in p orbital, further from the nucleus
what happens to IE between N (15) and O (16)
decreases - spin pair repulsion in the 3p orbital of O, repulsion makes it easier to remove
what is ionic bonding
the strong electrostatic attraction between oppositely charged ions
what increases ionic bonding strength
greater charge - stronger bonding
smaller radius - can pack closer so stronger
how do you measure ionic bonding strength
energy required to separate ions to infinity
what’s evidence for the existence of ions
electrolysis - copper (II) chromate - green goes to blue and yellow
what is covalent bonding
the strong electrostatic attraction between two positive nuclei and the shared electrons in the bond. from the overall of two orbitals, each containing an electron
pi vs sigma
sigma is s orbital overlap or end on overlap of p orbitals
pi is sideways overlap of two p orbitals - makes two areas of high electron density above and below the molecule, weaker than sigma
what is the bond energy
the energy required to break one mole of a covalent bond into gaseous states
What’s weird about ammonium chloride, AlCl3
dative covalent bonds with itself (LP on Cl and Al) makes a dimer
what is a dative bond
when an atom with a lone pair can donate its pair of electrons to form a covalent bond with an electron deficient atom
what’s the tetrahedral bond angle
109.5
what is electronegativity
the ability of an atom to attract the bonding electrons in a covalent bond, shown on the Pauling scale
what increases electronegativity
decreasing atomic radius
decreasing shield
increasing nuclear charge
decreases down the group
increases across the period
what is the continuum
of bonding types
polar covalent bonds are between pure covalent and pure ionic bonds. a polar bond is a covalent bond with some degree of ionic character
how do London forces form
electron density fluctuates
when unsymmetrical, instantaneous dipole created
induces a dipole in another molecule
positive attracted to negative, temp attraction
bigger mc has stronger forces due to more points of contact. increases frequency and magnitude of temp dipoles due to more electrons
branches reduce pts of contact
PD PD vs ID ID strengths
individually PD PD is stronger, but ID ID more significant as PD PD only works in one direction
why does water have lower density as a solid
packed in an open lattice due to long bond lengths of H bonds
define metallic bonding
the strong electrostatic attraction between the lattice of metal ions and the sea of delocalised electrons.
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