periodic table- 6

features of Mendeleev’s periodic table

• element arranged in order of increasing atomic mass

• elements arranged in groups and periods

• some elements swapped to allow atoms with similar properties to be grouped together

• left gaps for undiscovered elements

features of modern periodic table

• elements arranged in order of increasing atomic number

• noble gases present

• no gaps for undiscovered elements

• separate block of transition metals between group 2 and 3

• actinides and ianthanides present

what is a group

• vertical column in periodic table

• have similar chemical properties

• same N.O of electrons in outer shell

what is a period

• a horizontal row in periodic table

what is group 1

• alkali metals- very reactive

• first 3 are less dense than water

• all stored in oil to prevent reaction with air or water vapour

• soft (get softer as you go down)

• shiny when freshly cut

• all grey solids

what is group 2

Alkaline Earth metals- reactive metal

what is group 7

• halogens

• reactive non-metal

• all diatomic

• toxicity drecreases as you go down

what is group 0

noble gases- unreactive non-metal

malleable meaning

can be hammered into shape

ductile meaning

easily drawn into wire

sonorous meaning

makes a ringing sound when struck

metal properties

• high melting point

• malleable

• sonorous

• ductile

• conducts heat and electricity

properties of non- metal

• low melting point (except diamond and graphite)

• not malleable

• not sonorous

• not ductile

• doesn’t conduct heat or electricity (except graphite and graphene)

what are the gases

• 11

• hydrogen nitrogen oxygen fluorine chlorine and the noble gases

what are the liquids

bromine and mercury

risks and prevents of reacting water with group 1 metals

• metals can react with water in skin- use tweezers to prevent burning

• metal hydroxide solutions are corrosive- wear safety goggles, safety screen use large volume of water

• metal catches on fire- goggles, safety screen, small piece of metal

observations of lithium in water

• floats on surface of water

• moves around

• fizzes, gas given off

• disappears

• heat given off

observations of sodium in water

• same as lithium

• metal melts into tiny ball

observations of potassium in water

• same as lithium

• cackle at the end of reaction

• lilac flame

why does the reactivity increase as the group goes down

• depends on how easily it is to lose the electron in the outer shell

• to remove the electron the electrostatic attraction between the negative electron and the positive nucleus must be overcome

• the further away the outer electron the less attracted its to the positive charge

group 1 compounds

white, dissolve in water to give colourless solutions

fluorine properties

• F2

• Yellow

• Gas at room temperature

chlorine properties

• Cl2

• yellow-green

• Gas at room temperature

bromine properties

• Br2

• red-brown

• liquid

iodine properties

• I2

• grey-black

• liquid at room temperature

astatine properties

• At2

• black

• solid

• radioactive

sublimation definition

the change of state from a solid directly to gas on heating

why does the reactivity decrease as group 7 goes down

• the number of shells increases as you go down 🔺the distance between the nucleus and outer shell electrons increases

• electron is less attracted to the positive charge 🔺more difficult for the atom to attract an electron

what is a displacement reaction

the more reactive halogen is added to the halide solution

properties of group 1

• low melting point

• low density

• very reactive in water

• white compounds

properties of transition metals

• high melting point (except mercury)

• high density

• not reactive in water (some do with steam)

• can form ions with different charges

• coloured compounds

colour of copper (ll) oxide

black solid

colour of copper (ll) carbonate

green solid

colour of hydrated copper (ll) sulfate

blue solid

colour of any copper (ll) salt in solution

blue solution

colour of anhydrous copper sulfate

white solid