FINAL BUFFER Flashcards
Alkali metals
Elements found in Group 1 of the periodic table
Why are they called alkali metals?
Because when reacted with water they form alkaline solutions
What are the typical poroperties of Group 1 elements?
Shiny when freshly cut, good conductors of electricity, solid at room temperature, soft
As you go down the Group 1 Elements…
their density increases and their melting point decreases and reactivity increases
Why are Group 1 elements stored in oil?
To make sure they are not exposed to oxygen which they react rapidly with
alkali metal + water =
metal hydroxide + hydrogen
How does lithium react with water?
fizzes steadily and slowly disappears
How does sodium react with water?
melts to form a silvery ball, fizzes vigourously and quickly disappears
How does potassium react with water?
immediately ignites, burns with a lilac flame and very quickly disappears
Explain the trend in reactivity in Group 1 Elements
All atoms in Group 1 have one electron in their outer shell. The easier it is for an atom of a Group 1 Element to lose its outer electron, the more reactive the element is due to forces of attraction between the negatively charged electron and positively charged nucleus.
What do Group 7 elements exist as?
diatomic molecules with weak intermolecular forces
What is fluorine at room temperature?
a pale yellow gas
What is chlorine at room temperature?
a green gas
What is bromine at room temperature?
orange-brown liquid that vapourises easily
What is iodine at room temperature?
a shiny grey-black crystalline solid that sublimes to form a purple vapour
As you go down Group 7…
density increases, melting and boiling points increase, reactivity decreases
Halogens
Group 7 elements which react with metals to produce salts
Explain the trend in reactivity for halogens
All halogens have seven electrons in the outer shell. The easier it is for a halogen atom to gain an outer electron, the more reactive the element is due to forces of attraction between the electrons and the nucleus.
Halide
a compound containing a Group 7 element and another element usually hydrogen or a metal
What happens in a halogen displacement reaction?
a halogen will displace a less reactive halogen from its halide ions in solution
Noble gases
Unreactive elements found in Group 0 of the periodic table
Why are noble gases so unreactive?
They havecomplete outer shells meaning they have no tendency to lose or gain electrons to form ions
What do noble gases exist as?
monoatomic molecules with very weak forces of attraction between them
Why do noble gases have such low boiling points?
Having weak forces of attraction between atoms means these forces are very easily overcome by heating
As you go down Group 0…
attractive forces between atoms get stronger and boiling point increases and density increases
Why do noble gases have very low densities?
Their atoms are very far apart in the gas state
Transition metals
Metals found between Group 2 and Group 3 on the periodic table
What are the properties of transition metals?
shiny when freshly cut, good conductors of electricity, strong, malleable
Compared to alkali metals, transition metals…
are stronger and harder, have higher densities, have have higher melting points (except for mercury)
How do you detect carbon dioxide?
Bubble carbon dioxide through limewater (calcium hydroxide solution) and it will turn cloudy white if there is CO2 [as the reaction between limewater and CO2 produces a white precipitate of calcium carbonate]
How do you detect chlorine?
Hold damp blue litmus paper near a container that holds chlorine and if it is present then the paper will turn red then white
How do you detect hydrogen?
Hold a lighted splint near the mouth of a container of gas and it should ignite with a squeaky poop at the presence of hydrogen
How do you detect oxygen?
Hold a glowing splint near a container of oxygen and if it is present the splint should relight
Flame test colour for lithium ion
red
Flame test colour for sodium ion
yellow
Flame test colour for potassium ion
lilac
Flame test colour for calcium ion
orange-red
Flame test colour for copper ion
green-blue