period table Flashcards
element
a substance that consists of only one type of atom and can’t be broken down into any simpler substances by chemical means
malleable
can be hammered into shape
ductile
can be drawn into wires
sonorous
clangs when struck
group
a vertical row in the period table
period
a horizontal row in the period table
displacement reaction
a reaction in which a more reactive element takes the place of a less reactive element in a compound
diatomic
two atoms covalent bonded in a molecule
sublimation
the change of state from a solid directly into a gas when heated
how did mendeleev arrange the elements
-in order of increasing atomic mass
-elements with similar properties kept in groups
-used creative thought and left gaps for undiscovered elements
-accurately predicted properties of undiscovered elements
describe todays periodic table
-there are no spaces
-arranged in order of increasing atomic number
-has the noble gases
-the transition metals are grouped together in a separate block
differences between mendeleev’s and todays period table
-mendeleevs was arranged in order of atomic mass, todays is in order of atomic number
-the modern has noble gases mendeleevs didn’t as they hadn’t been discovered
-todays has the transition metals block mendeleevs didn’t
-todays has lanthanides and actinides mendeleevs didn’t
-todays has more elements and no spaces
how can you tell if it’s a solid liquid or gas for the meting and boiling points
-melting and boiling point above room temperature means it’s a solid
-melting point below room temperature and boiling point above room temperature means it’s a liquid
-melting and boiling point below room temperature means it’s a gas
what’s the name of group 1 elements
alkali metals
name of group 2 elements
alkaline earth metals
name of group 7 elements
halogens
name of group 8 elements
noble gases
what does period number tell us
the number of shells of each atom in that period
what does group 1 contain
-reactive metals
-all have one electron in their outer shell
why are group one elements so reactive
-only have one electron in their outer shell
-they only need to lose one electron to gain a full outer shell and become more stable
density of alkali metals
alkali metals have a low density and lithium sodium and potassium are less dense than water therefore when added to water they float on the surface
storage of group 1 elements
stored in oil because they react with oxygen and moisture in the air
what do alkali metals look like when cut
-can be cut easily with a knife
-initially shiny
-quickly tarnished with air
safety precautions of alkali metals
-use small pieces of metal
-use a safety screen to prevent metal sparking out
-wear safety glasses
-handle with tweezers
general reaction of alkali metals with water
metal + water —> metal hydroxide + hydrogen
observation of lithium in water
-heat released
-moves on water surface
-bubbles
-lithium disappears
-colourless solution is produced
observations of sodium in water
-heat released
-melts into a tiny ball
-moves on water surface
-bubbles
-sodium disappears
-colourless solution produced
observations of potassium and water
-lilac flame
-melts into a tiny ball
-moves on waters surface
-bubbles
-potassium disappears
-colourless solution produced
-heat released
balanced equation of lithium with water
2Li+2H20 -> 2LiOH+H2
balanced equation of sodium with water
2Na+2H2O -> 2NaOH+H2
balanced equation of potassium and water
2K+ 2H2O -> 2KOH+H2
what happens to reactivity when going down group 1
-reactivity increases
-as group is descended the atoms get bigger
-outer shell electron is further away from the nucleus so is easier to remove as outer negative electron is less attracted by positive nucleus
what happens to group 1 metals when they react
-they lose their electron
-they become an ion with a 1+ charge
why do all group 1 metals react the same way
-they all have one electron in their outer shell
-so they all have to lose 1 electron when react to form a 1+ ion
colours of group 1 compounds
-all group 1 compounds form white solids
-when they are dissolved they form colourless solutions
what does group seven contain
-reactive non metals
-all elements have seven electrons in their outer shell
-all diatomic
-all toxic and must be used in the fume cupboard
physical properties of fluorine
-gas
-yellow
physical properties of chlorine
-gas
-green
physical properties of bromine
-liquid
-red brown
physical properties of iodine
-solid
-grey
what happens as you go down group seven
-higher melting/boiling points
-atom size increases
-reactivity decreases
-colour gets darker
physical properties of astatine
-solid
-black
why are group seven elements so reactive
-seven electrons in their outer shell
-only need to gain one electron to get a full outer shell and become stable
describe iodine in sublimation
-grey black crystals as a solid
-purple vapour as a gas
test for chlorine
-put damp litmus paper into a test tube
-paper turns red then bleaches
what happens to reactivity when going down group 7
-reactivity decreases
-as group descends atoms get bigger
-outer shell is further from positive nucleus so more difficult to attract an electron
what happens to group 7 elements when they react
-name changed from ine to ide
-they gain an electron
-they become an ion with a 1- charge
why do all group 7 elements react the same way
-they all have seven electrons in their outer shell
-they all gain one electron when they react to form a 1- ion
observations of chlorine with potassium bromide
colourless to orange
observation of chlorine with potassium iodide
colourless to yellow/brown
observations of bromine with potassium bromide
colourless to yellow/brown
halogen displacement experiment method
-add 1cm cubed of chlorine water to two test tubes
-add about same amount of potassium iodide to one and potassium bromide to the other
-record any observations
-repeat with bromine water (potassium chloride and iodide)
-repeat with iodine (potassium chloride and bromide)
noble gases properties
-colourless
-inert
what does inert mean
unreactive
why are they so unreactive
they gave full outer shells so do not need to lose or gain any electrons to become more stable
what happens to boiling point when going down the group
increase
why do boiling points increase going down the group
the van der waal’s forces get stronger as you go down the group so more energy is needed to break apart the forces between atoms
why are nobles gases’ boiling points low
-they are non metals and are monoatomic (exist as separate atoms not molecules)
-this means they only have very weak Van der waals forces between their atoms
-these require very little energy to break apart the atoms
where are the transition metals
placed in a large block between group 2 and group 3
properties of transition metals
-good conductors of heat and electricity
-malleable
-ductile
-high melting points
-usually hard and tough
-high densities
-they can form ions with different charges
-their compounds are often coloured
charge on ions of transition metals
variable charges
transition metals reaction with water
slow
group 1 metals reaction with water
very vigorous
colour of compounds of transition metals
rust
