3 periodicity Flashcards
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
what defines basic oxides
they dissolve in water to produce basic solutions
what defines acidic oxides
they dissolve in water to produce acidic solutions
Na2O (s) + H2O (l) →
2NaOH (aq)
MgO (s) + H2O (l)→
Mg(OH)2 (aq)
P4O10 (s) + 6H2O (l)→
4H3PO4 (aq)
SO3 (g) + H2O (l) →
H2SO4 (aq)
3NO2 (g) + H2O (l) →
2HNO3 (aq) + NO (g)
Cl2O7 (l) + H2O (l) →
2HClO4 (aq)
Cl2O (g) + H2O (l) →
2HClO (aq)
alkali metals properties
relatively soft
first 3 have low enough densities to float on water
melting and boiling points decrease down the group as the metallic bond gets weaker as ionic radii increase
stored in oil to prevent reactions with air
reactivity increases down the group
low ionisation energies of alkali metals mean they are reactive. what do they form with water
metal hydroxides and hydrogen gas
properties of halogens
reactive group of non metal elements
reactivity decreases down the group
chlorine properties
dense pale green gas
smelly and poisonous
occurs as a chloride in the sea
strong oxidising agents
bromine properties
deep red liquid with red brown vapour
smelly and poisonous
occurs as a bromide in the sea
iodine properties
grey solid with purple vapour
smelly and poisionous
occurs as iodidies and iodates in some rocks and in seaweed
what is a displacement reaction
in which the more reactive halogen displaces the ions of the less reactive halogen from solution.
what happens whrn chlorine is added to a colourless solution of potassium bromide
it turns brown due to the formation of aqueous bromine. cyclohexane allows the change to be seen more visibly, as because it is polar, it will forma layer above the reaction mixture
what happens when an aqueous solution of chlorine is added to a solution containing iodide ions
the iodide ions have been oxidised eto form aqueous iodide. a purple layer is observed in the layer of cyclohexane because of the formation of iodine with dissolves in cyclohexane.
do Al2O3 and SiO2 react well and are soluble
no poorly reactive and poorly soluble
structure of Na2O, MgO and Al2O3
ionic
structure of SiO2
covalent macromolecule (which is why its so insoluble)
structure of P4O10, SO2, SO3
simple covalent
which period 3 oxides are alkaline
Na2O
mgO
which period 3 oxide is amphoteric
Al2O3
alumina
which period 3 oxides are acidic
SiO2
P4O10
SO2
SO3
what happens in the reaction of Na2O and water
forms sodium hydroxide
what happens in the reaction of MgO
forms magnesium hydroxide
what happens in the reaction of Al2O3 with water
neutralises the acid
what happens in the reaction of Al2O3 with sodium hydroxide
makes a neutral salt (solution remains neutral)
what happens in the reaction of SiO2 with sodium hydroxide
neutralises (hence why we classify it as a base)
what happens in the reaction of P4O10 with water
forms phosphoric acid H3PO4
what happens in the reaction of SO2 with water
forms sulfurous acid
H2SO3
what happens in the reaction of SO3
forms hypochlorous acid
what is Z
atomic number
what is nuclear charge
total chare of all the protons in the nucelus of an atom
group 1 is
alkali metals
group 2 is
alkaline earth metals
group 17 is
halogens
goup 18 is
noble gases
what are lanthanides and actinides
metallic elements that make up the f block
the s block occupies
groups 1 and 2
the p block occupies
group 13 to 18
d block occupies
group 3 to 12
f block occupies
elements at the bottom