Atomic structure/periodic table/bonding/structure recall

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.