Reaction of Common Metals and Properties of Hydrogen Flashcards
Group 1 refers to
the alkali metals
why are group 1 called alkali metals
because their hydroxides (compound with OH) are all soluble in bases (aka they are alkalis)
most important common characteristics of group 1 metals
a) single electron in the outermost orbital of their atoms
b)low energy required to detach this electron from the atom (ionization energy(
what is the exception to the group 1 metals
hydrogen
why is hydrogen an exception to group 1 metals
a) it is a diatomic gas while other elements are metals
b) hydrogen can form an anion (H-) while alkali metals CANNOT
describe the salt-like hydrides made by group 1
a) have similar structure to alkali HALIDES (metal and halogen react)
b) EXTREMELY reactive with water
what are the products formed when a salt-like hydride reactions with water (group 1)
metal hydroxide and hydrogen has
how can underlying electrons in group 1 metals be removed
ONLY with very high energies
what is the oxidation state of alkali metals in their compounds
+1
describe motion of electrons when group 1 metals are SOLID
electrons are held LOOSELY and they can readily pass from association with on atom to another
do group 1 metals show high or low degree of conductivity
high - based on how electrons pass readily from one atom to another when the metals are solid
are the alkali metals the most active of the metals and why or why not
yes - because their outer electron is held so loosely
can group 1 metals be easily recognized by a flame test
yes
sodium flame test
yellow
how can one detect potassium from sodium in a flame test
potassium is much MUCH less sensitive than the sodium one, so you have to look through blue glass to cut out the yellow of the sodium light to detect the potassium (if sodium is in high amounts)
group 2 are the
alkaline earth metals
what are the elements with 2 valence electrons
group 2
(magnesium, calcium, strontium, barium and radium)
group 12
(zinc, cadmium, mercury)
what are common characteristics of group 2 and 12
a) group 2 elements have the same core electron configuration as the preceding noble gas
b) group 12 elements have core electrons with EIGHTEEN electrons in the outermost CORE shell
describe beryllium and magnesium compared to the other elements in their group
are smaller and have more acidic cations
why were beryllium and magnesium often classified with group 12 elements instead of group 2
because of the fundamental differences in their structures (that they are smaller and have more acidic cations)
describe the properties of group 2 hydroxides (EXCLUDING beryllium and magnesium)
distinct alkaline properties (basic_
what is the oxidation state of group 2 metals
+2
what does group 2 oxidation state mean
both their outer electrons are ALWAYS lost when element enters a chemical reaction
describe the ionization energies of the HEAVIER elements of group 2 and 12
as low as the alkali metals (reacts more readily with water to lose its electrons)
what happens when group 2 metals react with water
form the specific cation (+2), hydroxide (OH-) and hydrogen gas
is the reaction between group 2 metals with water slower or faster than group 1
slower
do group 2 metals react with acids
YES - very rapidly
how do group 2 metals not undergo rapid oxidation under lower temps
because their surfaces are protected by oxide films
- ex. beryllium and magnesium
what are the two of group 2 metals that DO NOT sufficiently impact the flame test
beryllium and magnesium
what are some examples of compounds that have a very strong flame test? some that do not?
a) chlorides or nitrates
b) oxides or sulfates (due to low volatility)
do zinc and mercury (of group 12) have higher or lower ionization energy than group 2 and why?
higher - lack of reactivity of these metals with water
what is the oxidation state of zinc
+2
how can zinc be easily oxidized
with the formation of hydrogen gas (in both acid or basic solutions)
what are two examples of amphoteric nature of elements
zinc and aluminum
what is the compound formed when aluminum reacts with bases
Al(OH)4-
what of the chemicals used in this lab are extremely dangerous when in contact with moisture
sodium and potassium
what of the chemicals used in this lab is spontaneously flammable in the air
potassium
what indicator was used in station 1 (reactions of active metals with water)
phenolphthalein as it is colourless in acids or neutral solutions and pink in basic)
what metals were used in station 1 of this lab (reactions of active metals with water)
- sodium
- potassium
- calcium
- magnesium
- zinc
what was the relative reactivity series of station 1 (reactions of active metals with water)
K+ > Na+ > Ca2+ > Mg2+ = Zn2+
most reactive alkali metal with water balanced equation
2K(s) + 2H2O(l) —-> 2KOH(aq) + H2(g)
most reactive alkaline EARTH metal with water balanced equation
Ca(s) + 2H2O(l) —-> Ca(OH)2(aq) + H2(g)
what happened when sodium was reacted with water
immediately reacted and started fizzing and turning into a silver ball before dissolving
b) phenolphthalein turned pink = base present
what happened when potassium was reacted with water
immediately began to smoke and react with the water
fizzes and dissolves FASTER than sodium
phenolphthalein turned pink = base present
what happened when calcium was reacted with water
a) immediately sank to the bottom before rising to the surface again
b) it slowly broke apart and some bubbles were observed
c) did react with water but NOT as fast as either potassium or sodium
d) phenolphthalein turned pink = base present
what happened when magnesium was reacted with water
a) there was NO immediate reaction
b) phenolphthalein = no colour change = acidic or neutral solution
what happened when zinc was reacted with water
a) immediately sank to the bottom of the water but NO reaction seemed to occur
b) phenolphthalein = no colour change = acidic or neutral solution
how to clean up station 1 waste (reactions of active metals with water)
a) solutions go down fume hood sink with lots of water
b)metal still in the beaker is thrown in the SOLID CHEIMCAL WASTE BUCKET
station 2 of this experiment was
flame test of metal ions
how to adjust airflow of a bunsen burner
turn the tube that connects the end (where flame is) and the base
how to adjust gas flow of a bunsen burner
by turning the valve (or ring on the base)
- more gas = higher flame
- less gas = lower flame
describe the steps of conducting a flame test
a) heat a platinum wire in the hottest part of the flame
- if it changes flame colour = clean wire by dipping in 6 M HCl than dipping in RO water before heating again
b) dip the cleaned wire into the solution then heat in the hottest part of the flame
c) clean the wire as in part a and repeat with the next solutions
what is the danger with 6 M HCl
causes severe burns
what were the metals used in station 2 of this experiment (flame test of metal ions)
a) calcium
b) Strontium
c) barium
d) lithium
e) sodium
f) potassium
of the metals used in station 2 (flame test of metal ions) what were the two flames looked at through didymium glasses
sodium and potassium
what is the clean up procedure of station 2 (flame test of metal ions)
all solutions washed with RO water into the HEAVY METAL WASTE CONTAINER
what was station 3 of this experiment
reactions of metals with acid and alkali for the identification of hydrogen
how was station’s 3 reaction done (reactions of metals with acid and alkali for the identification of hydrogen)
a) a spatula-tip full of the metal was added to a large test tube that was filled with 1-2 cm of 6 M HCl
b) the test tube is held with a part of tongs and the reaction is agitated (shaken slightly) to start
c) light a wooden splint over the Tirrill burner and hold it over the opening of the test tube
- do not let splint touch sides of test tube
- use tongs to hold splint AT ALL TIMES
what are the two metals used for station 3 (reactions of metals with acid and alkali for the identification of hydrogen)
zinc and aluminum
the station 3 experiment was conducted twice for each metal, how did the trials 1 and 2 differ
a) trial 1 was using 6 M HCl
b) trial 2 was using 10 M NaOH
what is a safety note when using NaOH
a) it is a strong BASE and can cause burns on skin
at station 3, how does on know if hydrogen is present in any of these reactions
there will be an audible pop when ignited
how is station 3 cleaned up
a) all solutions go into the special waste container at the station
b) HCl and NaOH bottles are capped
why does hydrogen have a higher first ionization energy than group 1 metals
- electrons are held closer to the nucleus than the group 1 metals
why can core electrons of group 1 metals ONLY be removed by high energies
they are closer to the nucleus = feel a stronger pull to the nucleus
what of the metals used in station 2 was EXPECTED to have the least reaction with water
zinc because of its high ionization energy
balanced reaction of zinc and hydrochloric acid
Zn(s) + 2HCl(aq) —–> ZnCl2 (aq) + H2(g)
balanced reaction of zinc and sodium hydroxide
Zn(s) + 2NaOH (aq) ——> Na2ZnO2 (aq) + H2(g)
balanced reaction of Aluminum and hydrochloric Acid
2Al(s) + 6HCl(aq) —–> 2AlCl3(aq) + 3H2(g)
balanced reaction of aluminum and sodium hydroxide
2Al(s) + 2NaOH (aq)+ 6H2O (l) ——-> 2Na[Al(OH)4] + 3H2(g)
describe the reaction of zinc and HCl
- reaction was immediate when zinc was reacted with HCl (bubbles and fizzing)
- flames burned hotter before the reaction was over
- a pop is heard which indicates hydrogen is present
describe the reaction of zinc and NaOH
- reaction was very slow to start
- no pop sound was detected = no hydrogen present
describe the reaction of aluminum and HCl
- reaction needed heat to start
- similar reaction was observed to zinc after heating (bubbles and fizzing)
- no pop was heard = no hydrogen present
describe the reaction of aluminum and NaOH
- heat was added to start the reaction
- a pop can be heard during the reaction with heat
calcium flame test colour
orange/red flame
strontium flame test colour
red
barium flame test colour
green
lithium flame test colour
red
potassium flame test colour
violet
