Unit1Topic6 - The Periodic Table Flashcards
The Newlands structure of the Periodic Table
- arranged elements in order of increasing atomic mass
- noticed similarities between each 8th element (called the Newlands Octaves)
The Mendeleev structure of the Periodic Table
- left gaps for undiscovered elements
- arranged elements in groups and periods
- separated the metals and non-metals
- arranged elements in order of increasing atomic mass
How the modern Periodic Table differs from Mendeleev
- no gaps
- noble gases
- elements arranged in order of atomic number
- actinides and lanthanides
Name of group 1
Alkali metals
Name of group 2
Alkaline earth metals
Name of group 7
Halogens
Name of group 8
Noble gases
Name of block between groups 2 and 3
Transition metals
Which elements are the only liquids on the Periodic Table?
Br and Hg
Across a period the…
- atoms decrease in size
- elements change from metals to non-metals
- oxides of the elements change from basic to acidic
- semi-metals (properties between metals and non-metals) are found between metals and non-metals e.g. silicon
Why do the atoms gradually decrease in size across a period?
The extra electron going into the same shell and the extra positive charge on the nucleus, caused by the extra proton, increases the attraction on the shells pulling them closer to the nucleus.
As you go down groups 1 and 2…
- bigger atoms (there is one extra full shell of electrons for each row you go down)
- more reactive (outer electron is more easily lost as further from the nucleus)
- more dense
- even softer to cut
- lower melting point / boiling point
Metal + water ->
Metal hydroxide + hydrogen
Metal + oxygen ->
Metal oxide
Metal + acid ->
Salt + hydrogen
Metal + halogen ->
Metal halide
Potassium in water observations
- bubbles of gas / fizzes
- moves across surface
- potassium disappears
- catches fire / burns with a lilac flame
Why is lithium stored under oil?
It could react with the moisture in the air
Why should caesium never be added to water?
It’s highly reactive (explosive)
Lithium in water observations
- fizzes
- moves across surface
- sodium disappears
- melts into a ball
How would you show the final solution contained potassium hydroxide?
Use Universal indicator, which will turn dark blue
Why do all group 1 metals have similar chemical properties?
They all have 1 electron to lose in their outer shell
Fluorine (F2) appearance
Pale yellow gas
Chlorine (Cl2) appearance
Pale green gas
Bromine (Br2) appearance
Red-brown volatile liquid
Iodine (I2) appearance
Dark black solid gives purple vapour
As you go down group 7…
- bigger atoms
- less reactive
- less soluble (although none of the halogens are very soluble)
- increasing melting point / boiling point
- change of state from gas -> liquid -> solid
Physical properties of chlorine
- pale green gas
- heavier (denser than air)
- toxic
- slightly soluble in water
- bleaches damp litmus paper (this is the test for chlorine)
Source of chlorine
Electrolysis of sodium chloride (brine)
Uses of chlorine
- manufacture of PVC
- bleach
- water sterilisation (used to kill germs in swimming pools and drinking water)
Displacement reaction - a …… ………… halogen can displace a …… ………… halogen from a solution of its salt
More reactive
Less reactive
Displacement reaction - when chlorine reacts with potassium bromide
Solution turns orange (bromine in water is produced)
Displacement reaction - when chlorine reacts with potassium iodide
Solution turns brown (iodine in water is produced)
Displacement reaction - when bromine reacts with potassium chloride
Solution remains orange (no reaction)
Displacement reaction - when bromine reacts with potassium iodide
Solution turns brown (iodine in water is produced)
Displacement reaction - when iodine reacts with potassium chloride
Solution remains brown (no reaction)
Displacement reaction - when iodine reacts with potassium bromide
Solution remains brown (no reaction)
Physical description of bromine
- liquid
- red-brown
Most common use for the noble gases
Neon, glowing signs
Colour helium produces as a neon, glowing sign
A pale pink light
Properties of all metals
- hard
- shiny
- high melting / boiling points
- malleable and ductile
- sonorous (produce sound when struck)
- conduct heat and electricity
- strong
Trends within a group
- have the same number of outer electrons
- similar properties
- atom size increases as you go down a group
Metals are found on the …… …… ……, non-metals on the …… …… ……
Metals - left hand side
Non-metals - right hand side
Metals form metal oxides which are…
Non-metals form oxides which are…
Some elements in the middle of the table form oxides that show… These are called…
Metals form metal oxides which are basic (remember a soluble base is called an alkali)
Non-metals form oxides which are acidic (e.g. sulfur dioxide SO4)
Some elements in the middle of the table form oxides that show acidic and basic properties (e.g. aluminium oxide). These are called amphoteric oxides.
