the periodic table Flashcards
what is the periodic table?
its a list of elements arranged in order of increasing proton numbers
what is a group?
its a vertical coloumn of elements
there are 8grps, I-VII n O
it runs frm top to bottom
what is a period?
its a horizontal coloumn of elements
there are 7 periods
runs frm left to right
Periodic trends:
metallic n non-metallic properties across the period
from left to right across a period, thr is a decrease in metallic properties n an increase in non-metallic properties:
from very metallic to metalloids(Silicon) to non-metallic
better RAs to better OAs
from basic to amphoteric to acidic
metallic properties down a grp
thr is an increase in metallic properties
non-metallic properties down a grp
thr is a decrease in non-metallic properties
why is the metallic properties down a grp as such?
going down a grp, the size of the atoms increases so atomic radius increases so the -vely charged valence e of an element will b further away frm the +vely charged nucleus so an element down a grp will thus lose its valence e more easily so its more reactive
electronic structure:
we can obtain the elctronic config frm
the element’s proton no.-> deduce period n grp no.
the no. of eshells is the same as
the period no. of the element
the no. of valence e is the same as
the grp no. of the elements
elements w the same no.of valence e hv
similar chemical n physical properties tht r determined by no. of valence e
group 1 elements: Alkali Metals
all the elements hv similar properties since thy belong in the same grp
the physical properties of alkali metals
they are soft n can b cut thru easily
low mp n bp which decreases down the grp
low densities which increases down the grp
thy r vry shny metals but whn thy r cut since thy r so reactive thyll oxidise n bcome black
chemical properties of alkali metals
- they are highly reactive metals so they have to be stored in oil to prevent it frm reacting w air n water
- thy can just lose 1 valence e to attain noble gas electronic structure
- reactivity increases down the grp bcos down the grp, atomic radius increases so it is easier to lose the valence e since the electrostatic forces of e btwn the +vely charged nucleus n negatively-charged valence e gets weaker so its easier to lose e
reaction tht alkali metals can take part in
- they can react w cold water to form alkali + hydrogen
they r all exothermic!!
are alkali metals powerful oa or ra?
powerful ra!! since all alkali metals form ions w a charge of +1 by losing 1e frm the outer shell which thy can lose easily/readily
reducing power increases down the grp as the metals has a higher tendency to lose e down the grp( n bcome oxidised)
alkali metals form what kind of cmpnds?
form ionic cmpnds n their cmpnds hv similar chemical formulas n r soluble in water
whn placed in a fire, Li glows:
bright red
whn placed in a fire, Na bcomes:
bright yellow
whn placed in a fire, K produces a:
violet colour
whn placed in a fire, rubidium is:
dark red
whn placed in a fire, caesium is:
light blue
Group 7 elements: Halogens;
physical properties of halogens
halogens r non-metals tht exist as diatomic covalent molecules w SMS(weak wander Waals FOA)
it has low mp bp which increases down the grp
it is coloured and the colour bcome darker/colour intensity increases down the grp
density increases down the grp
why does halogens have an increasing mp n bp down the grp?
down the grp the molecular masses/sizes of halogens increase so the vdwfoa btwn molecules increases so a highr amt of heat energy is req to overcome the foa so mp/bp increases
r halogens soluble in water?
all halogens r soluble in water no matter what state it is in
colour of F2(g)-> gas at rm temp!!
pale yellow
colour of F2(aq)
colourless
colour of Cl2(g)-> gas at rm temp!!
yellowish-green
colour of Cl2(aq)
colourless
colour of Br2(l)
reddish-brown
colour of Br2(aq) n Br2(g)
brown/ orangey brown
colour of I2(g)
violet
colour of I2(s)
black
colour of I2(aq)
reddish brown not yellowish-brown!
astantine
black solid
chemical properties of halogens:
- they are reactive non metals since thy hv 7 valence e n only require 1 e to achieve stable octet noble gas config
halogens react w metals to form?
salts-> called halides
reactivity of halogens increases or decreases down the grp? n why?
decreases down the grp bcos the atomic radius of the halogens increases down the group, so the esfoa between the +vely charged nucleus and -vely charged electron gets weaker right, so its harder to attract an electron down the grip, which is why reactivity decreases down the grp
r halogens powerful oa or ra? does their oxidising/reducing power increase or decrease down thr grp?
powerful oa’s! oxidising power also decreases down thr grp since OA is directly related to reactivity
halogen displacement rctns
a more reactive halogen will displace a less reactive halogen frm its halide sln
RMBR DO NOT SPLIT THE AQ STATES IN THE IONIC EQNS!!!!!
more reactive halogen + halide of less reactive halogen(the colour is decided by cation tho) -> salt + halogen(less-reactive one)
transition metals properties(4)
- high mp bp
- high densities
- variable oxidation states
- form coloured cmpnds: colour of hydrated compnd may b diff frm tht of the anyhydrous cmpnd-> helps us test for presence of H2O
uses of transition metals(2)
- used in dyes n paints to produce diff colours
2. used as catalysts-> increases SOR n remains chemically unchanged at the end of rctn
group VIII/0 elements-> Noble gases aka
inert gases or rare gases
properties of noble gases(7)
- non-metals
- monoatomic
- coloured gases at rm temp
- low mp n bp which increases down the grp
- insoluble in water
- do not form compounds
- bcos thy r UNREACTIVE-> dont lose, gain or share e bcos thy hv stable duplet(He) or octet electronic config
