Ions + Ionic Compounds 2 Flashcards
Rank metals from different groups in terms of metal reactivity
Group I > Group II > III > Transition metals
Why is Na more reactive than Mg and Al?
Na needs to lose only 1 e- to form cation, but Al needs to lose 2 e- to form cation. Twice the energy is needed to break the attraction between nucleus and OUTERMOST e- for Al compared to Na, thus it’s easier for Na to form cation
Why is K more reactive than Na?
Attraction bt outermost e- and nucleus decreases as no. of occupied e- shells increases due
to longer distance bt outermost e- and nucleus —> easier to lose outermost e- —> more reactive metal
Tin, platinum chem symbol
Sn, pt
Abundance of gases in air
N > O > Ar > CO2
Which metals can be burnt and form oxides?
K, Na, Ca, Mg, Al, Zn, Fe: burn + form oxides
Pb, Cu, Hg can’t burn but form oxides
Ag, Pt, Au: no reactions
Which metals need to be strongly heated for flame test?
Only K + Na are GENTLY HEATED
The rest up to Hg are strongly heated
Which metals form white powder when gently/strongly heated
K, Na, Ca, Mg, Al
Al burns with white flame
Mg flame test
Mg burns with BRIGHT WHITE flame
MgCl2 has no coloured flame
Zn, Fe, Pb, Cu, Hg flame test
Zn: white blue flame
ZnO: yellow powder when hot, white powder when cold
Fe: burns w/ yellow sparks
FeO: black powder
Pb: Orange powder when hot, yellow when cold
CuO: black powder
HgO: red
Colour of oxides of Grp I-III metals and colour of oxides of
Grp I-III metals oxides: white
trans metals oxides: usually coloured
EXTRA: how to store are + Cs
Store in vacuumed flask
Why are oxides usually in solid state
FOR BALANCING CHEM EQUATIONS: Ionic compounds + metals are in solid state at 25C
Vaporisation VS evaporation
Vaporisation: when temp is over a substance’s bp (eg: water over 100 is steam)
Evaporation: temp is lower than a substance’s bp but substance still in gaseous form (eg: water vapour)
Which metals react with water(g) but not water(l)
Mg, Al, Zn, Fe
Sn, Pb Cu and the rest X react with water
What can be OBSERVED when K reacts with water(l)?
K floats on water (lower density than H2O), moves quickly on water surface, turns into silvery ball + burns w/ lilac flame w/ hissing sound
Na: same but w/ golden yellow flame (Note: no gas bubbles bc not surrounded by water)
Mg/Ca + water observation
Ca sinks to bottom of water, colourless gas bubbles are evolved
A cloudy solution may be formed as Ca(OH)2 is slightly soluble on water
(Note: Ca may sink then rise up later as it’s pushed up by H2) (no flame is formed bc Ca isn’t in contact with O2)
Mg + steam observation
Metal gives white light
White powder is formed (Note: no gas bubbles bc no liquid H2O is involved)
Al + steam observation
White powder formed
(Al powder instead of Al foil should be used as Al foil has a layer of Al2O3 on top)
Zn+ steam obs
Powder is formed (hot: yellow, cold: white)
Fe + steam obs
FE3O4 (black powder) is formed
(Fe2O3 + FeO)
Name 3 polyatomic ANIONS formed from metals
(Purple) MnO4-, (Cr2O7)2-, (CrO4)2-
Iron (II) ion colour
Green
Iron(III) colour
Yellow
