3 periodicity
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groups go from
1-18
periods go from
1-6
what is the order of block/orbitals in the periodic table
s, d, p block
exception to the blocks/orbitals in the periodic table
helium
what does n mean
the outer energy level that is occupied by electrons
what are the d block elements called
transition metals
what are the f block elements called
lanthanoids and the actinoids
what is the atomic radius
half the distance between the nuclei of two bonded atoms of the same element
across a period atomic radius
outer electrons in same shell more protons in nucleus same amount of shielding so stronger attraction between nucleus and outer shell electrons so outer shell electrons pulled closer to nucleus DECREASE
down a group atomic radius
outer electrons are in a new shell many more protons in nucleus much more (whole new energy level) shielding so weaker attraction between nucleus and outer shell electrons INCREASE
what is shielding
inner electrons shield the outer electrons from the nucleus. this reduces the effective nuclear charge
why do cations have a greater electrostatic attraction
because they have fewer electrons to protons, and one less electron shell, meaning the distance is smaller.
are cations isotonic or not across a period
isotonic beacause same number of electrons but an increasing number of protons, so ionic radius decreases.
are anions isotonic or not across a period
not because they contain more electrons than protons, so are larger than parent atom. across a period the size decreases because number of electrons remains the same and number of protons increases.
what is first ionization energy
amount of energy needed to make a 1+ ion (in gas phase) by removing an electron depends on how strongly that electron is attracted.
what is effective nuclear charge composed of
charge on nucleus (number of protons) shielding from other electrons (shells)
why are paired electrons slightly easier to remove from atoms than unpaired electrons
the 2 electrons sharing an orbital will repel each other and have a lower ionisation energy
FIE down a group
nuclear charge increases shielding stays the same distance from nucleus decreases INCREASE
IE across a period
nuclear charge increases shielding increases distance from nucleus increases DECREASE
why does the type of bonding change across period 3
because of the change from metal to non metal oxides, the intermolecualr forces weaken, and they become gas or liquid. the difference in electrnegatiivty between the atoms means the type of bonding cahanges.
amphoteric def
can act as both an acid and a base
which period 3 oxides are basic
Na2O MgO
which period 3 oxides are amphoteric
Al2O3
which period 3 oxides are acidic
SiO2 P4O10 or P4O6 SO3 or SO2 Cl2O7 or Cl2O