F4 C4 CHEM (GROUP 1 4.4) Flashcards
whats group 1 known as?
alkali metal
are group 1’s elements metal? why?
yes because group 1 -13 are metals
first 3 elements in gorup 1?
lithium (Li)
sodium (Na)
pottasium (K)
which characteristic of these elements determines them to be in group 1?
number of valence electrons?
they have 1 valence electron
alkali metals appear as?
shiny grey solids
compare the hardness of alkali metal to a normal metal
alkali metals are soft that they can be cut by knife
compare the density of alkali metal to a normal metal
an alkali metal has a low density (float) compared to a normal metals which has a high density (sink) in water
compare the melting and boiling point of alkali metal to a normal metal
an alkali metal has a low melting and boiling point compared to a normal metal
why is the melting and boiling point of an alkali metal low?
shells filled with electrons of group 1 elements are attracted by weak metallic bond. little heat is required to overcome the forces of attraction
can group 1 elements conduct heat and electricity?
yes, these metals are good conductors
explain the density going down the group
moving down the group, the density increases because the increase in mass is greater than the increase in volume
explain the atomic size going down the group
going down the group, the atomic size increases because number of shells filled with electrons increases
explain the melting and boiling point going down the group
going down the group, the melting and boiling point decreases. this is because going down the group the atomic size increases and the the metallic bond is becoming weaker. little heat is required to overcome the forces of attraction
explain the hardness going down the group
alkali metals becomes softer going down the group
group 1 elements are very reactive. why?
group 1 elements are not stable yet. they’ll donate/lose/share one valence electrons to achiveve stable duplet/octet electron arrangement
what happens after the grp 1 element loses its electron?
these alkali metals becomes a positive ion with a +1 charge.
exp : Na+, K+
changes in chemical properties of alkali metals is from which aspect?
reactivity
what happens to the reactivity of the group 1 elements going down the group?
going down the group, the reactivity increases. this is because it’ll be easier for elements to lose/donate one electrons.
what’s another word for *increasing reactivity *?
more electropositive
Group 1elements can react with?
theres 3 things
water, oxygen, chlorine
whats the chemical equation for reaction on group 1 elements with water
Alkali metal + water—>
alkali + hydrogen
example (unbalanced equation) : Na + H20 –> NAOH (sodium hydroxide) +H2
explain the reaction of lithium (Li), an alkali metal, with water
- moves slowly on the surface of water with a “hiss” sounds
- produces colourless solution
- the colourless solution turns red litmus paper into blue
explain the reaction of sodium (Na), an alkali metal, with water
- moves rapidly on the surface of water with a “hiss” sound
- burn with yellow flame
- produces colourless solution
- the colourless solution turns red litmus paper into blue (alkaline solution)
explain the reaction of pottasium (K), an alkali metal, with water
- moves very rapidly on the surface of water with a “hiss” sound
- burn with purple flame
- produces colourless solution
- the colourless solution turns red litmus paper into blue (alkaline solution)
what’s the chemical equation of the reaction between alkali metal and oxygen
general equation
alkali metal + oxygen —> metal oxide (white solid)
example (unbalanced equation) : Na + O2 –> Na2O
can metal oxide (alkali metals that reacted with oxygen) dissolve in water?
yes
metal oxide produces alkali when dissolved in water again
Na2O + H2O –> 2NAOH
(balanced equation)
does the alkali metal produce hydrogen when dissolve in water? what about metal oxide?
yes alkali metal does but however metal oxide does not produce hydrogen
alkali metal : produce alkali + hydrogen
metal oxide : produce alkali only
EXPERIMENT
explain the reaction of lithium (Li) with oxygen
- lithium burns slowly with red flame
- white solid is produced
- white solid dissolves in water to produce colourless solution
- colourless solution changes red litmus paper to blue
EXPERIMENT
explain the reaction of sodium (Na) with oxygen
- sodium burns brightly with yellow flame
- white solid is produced
- white solid dissolves in water to produce colourless solution
- colourless solution changes red litmus paper to blue
EXPERIMENT
explain the reaction of pottasium (K) with oxygen
- pottasium burns very brightly with purple flame
- white solid is produced
- white solid dissolves in water to produce colourless solution
- colourless solution changes red litmus paper to blue
other than oxygen and water, gorup 1 elements can also react with ?
Chlorine
whats the chemical equation for the reaction of group 1 with chlorine
alkali metal + chlorine —> metal chloride (white solid)
example (balanced equation) :
2Na + Cl2 –> 2NaCl
alkali metals are shiny ____ .
grey solid
alkali metals when reacted with oxygen and chlorine will produce ____ solid
white
Can group 1 chloride dissolve in water? if yes, what’s produced?
Yes group 1 chloride dissolves in water to produce neutral solution
Note : group 1 oxide and hydroxide produces alkaline solution
EXPERIMENT
explain the reaction of lithium (Li) with chlorine
- lithium burns slowly with red flame
- white solid is produced
EXPERIMENT
explain the reaction of sodium (Na) with chlorine
- sodium burns brightly with yellow flame
- white solid is produced
EXPERIMENT
explain the reaction of pottasium (K) with chlorine
- pottasium burns very brightly with purple flame
- white solid is produced
List 2 safety precautions while handling alkali metals
- store alkali metals in parrafin oil
- put on gloves and take alkali metals using a forcep
- (extra) use small amounts of alkali metals as they’re very reactive
