3.1 periodic table Flashcards
where is the s-block?
groups 1 and 2
where is the p-block?
groups 3, 4, 5, 6, 7 and 8
where is the d-block?
transition metals
where is the f block
lanthanides and actinides (at the bottom)
define periodicity
trends in properties that are repeated and occur across the periods of the periodic table
define 1st ionisation energy
the energy required to remove 1 mole of gaseous electrons from 1 mole of a gaseous atom
state and explain the trends of ionisation energy across the periodic table
increases from left to right –>
- no extra shielding
- more protons
- smaller atomic radii
- greater nuclear attraction
- more energy required to remove electron
state 3 factors affecting 1st ionisation energy
atomic radius
electron shielding
nuclear charger
state and explain the trends in melting point across periods
- increases from group 1 to group 3:
• nuclear charge increases
• electrons feel greater nuclear attraction - peaks at group 4
• giant covalent structures require lots of energy to break their covalent bonds - decreases until group 8
• weak intermolecular forces - little energy to be broken
• peak in period 3 in sulphur because it has a larger electron cloud - S₈
state the trends in atomic radius
increases from top to bottom
increases from right to left
name 2 exceptions to the trends in ionisation energy
- between groups 2 and 3: group 3 elements have outer electron in p orbital, which is further from the nucleus and therefore easier to be removed. group 2 elements have outer electron in s orbital. group 2 > group 3
- between groups 5 and 6: outer electrons in group 6 elements experience “spin pair repulsion” as they are paired in an orbital. this repulsion makes them easier to remove. group 5 elements’ outer electrons are not paired group 5 > group 6
state the trend in nuclear charge in the periodic table
nuclear charge increases from left to right
define electron shielding
the repulsion of electrons in different inner shells. shielding reduces the attractive force between the nucleus and outer electrons.
state the trend in electron shielding in the periodic table
electron shielding increases down the group
define effective nuclear charge
the net positive charge experienced by an electron in an atom with more than one electron.
define malleable
something that can be hammered into shapes
define ductile
something that can be drawn into wires and rods
bigger positive ion = ______ bond strength. why?
bigger positive ion = WEAKER bond strength
eg. group 2 metals - each one makes a 2+ ion and have 2 mobile electrons per ion - for bigger ions, electrons are more spread out, making them less effective at attracting the big ions together - weaker bond strength/weaker electrostatic force
define successive ionisation energy
the sequence of first, second, third etc. ionisation energies needed to remove the first, second, third etc. electrons from each atom in one mole of gaseous atoms of an element
what is the trend of successive ionisations energy? why?
SIE increases each time 1st < 2nd < 3rd < 4th etc
because electrons are being removed from a more positive species/nucleus so this requires more energy.
name the group 2 elements in order
beryllium Be, magnesium Mg, calcium Ca, strontium St and barium Ba
state and explain the trend of melting point in group 2
MP DECREASES DOWN GROUP 2 because size of the ion increases = the bonding electrons become further from the positive nucleus = reduces attraction = lower melting point.
state and explain the trend of atomic and ionic radius in group 2
ATOMIC & IONIC RADIUS INCREASE DOWN GROUP 2 because more electrons = more shells = outer electron becomes further from nucleus
state the trend of electron configuration in group 2
each element gains another shell and moves to the next s-orbital. e.g. Be: …2s2 - Mg: …3s2 Ca: …4s2 etc.
state and explain the trend of 1st ionisation energy in group 2
IE DECREASES DOWN GROUP because atomic radius and electron shielding increases - electrons feel less attraction to the nucleus - easier to lose - less energy is required to remove them
describe and explain the SIE graph of a typical group 2 element
1st and 2nd IEs are close together and then the 3rd IE takes a large jump up - the 3rd electron is closer to the nucleus in a different shell - much more energy to be removed