Atomic structure and the Periodic Table

• Structure of atom

  nucleus containing neutron + proton
• Charges of particlesand relative mass

  Protons - +1, 1

  Neutrons - 0, 1

  Electrons - -1, 1/2000
• How particles are presented in an atom

  Atomic number - Number of protons, tells what element it is

  Mass numbers - Total number of protons and neutrons, relative mass

  Isotopes - Atoms of same element (same protons) can have different neutrons.
• What are the links between the electronic structure and its position in the periodic table

  Number of circles - Period number

  Number of electrons in outer shell - Group number

  Total number of electrons - Atomic number
• What is the trend of reactivity of group 1 metals

  Electrons are lost more easily

  Reactivity increases down the group as alkali metals react by losing an electron
• What is the trend of reactivity of group 7 metals

  Electrons are attracted less down the group

  Reactivity decreases down the group as there are more electron shells and so ability to attract another electron decreases
• Where are metals found in the periodic table?

  Left and centre of periodic table
• Where are nonmetals found in the periodic table?

  Right side going in a staircase from boron
• Electronic structure of the first 20 atoms

  Learn it
• Alkali metals

  . Group 1 react vigorously with water to create an alkaline solution and hydrogen

  . They all react with oxygen to make oxide

  . They all react with chlorine to form a white precipitate

  . Reactivity increases going down the group

  . All have characteristic properties due to single electron in outer shell
• Halogens

  . Similar reactions due to seven electrons in outer shell

  . React with metals to form ionic compounds in which halide carries an -1 charge

  . React with non metals to form covalent compounds where its a shared pair of electron

  . As you go down the group the relative molecule mass, melting and boiling point all increase

  . Decrease in reactivity means more reactive halogen can displace a less reactive one.
• What are the reaction of alkali metals with oxygen

  Lithium - Tarnishes slowly

  Sodium - Tarnishes more quickly

  Potassium - Tarnishes very quickly
• What are the reaction of halogen metals with water

  Chlorine, Bromine and Iodine are soluble in water.

  Florine acts vigorously with water
• How to test for hydrogen gas

  A burning splint - The splint is held at the open end of a test tube. A squeaky pop is heard if hydrogen is present
• Reactions of halogens with alkali metals

  A white precipitate

  reaction occurs very quickly
• What are uses of Chlorine

  Bleaching agent, disinfection of swimming pools
• What are the uses of Iodine

  antiseptic so can be used to prevent infection in hospital procedures
• Colour flames for Li, Na, K, Ca, Ba

  Li - Red

  Na - Orange - yellow

  K- Lilac

  Ca - Orange - Red

  Ba - Green
• Colour of Br, Cl, I with silver nitrate

  Cl - White - Ag(aq) + Cl(aq) --> AgCl(s)

  Br - Cream - Ag(aq) + Br(aq) --> AgBr(s)

  I - Yellow - Ag(aq) + + I(aq) --> AgI(s)
• Why are group 0 unreactive

  They all have a full outer electron shell which means they are already stable and so do not need to lose or gain electrons.
• physical trends of alkali metals

  densities increase down the group

  melting and boiling points decrease down the group
• reaction of a alkali metal and water produce

  fizzing that produces an alkaline solution and hydrogen
• what does iron + fluorine produce

  cold iron wool reacts almost instantly to form white iron fluoride
• what does iron + chlorine produce

  reacts vigorously to form an orange brown precipitate of iron chloride
• what does iron + bromine produce

  reacts quickly to form a red brown precipitate of iron bromide - has to be warmed
• what does iron + iodine produce

  reacts slowly in iodine vapour to form a grey iron iodide precipitate - has to heated strongly
• relative reactivities of halogens as precipitation reactions

  decrease in reactivity down halogen means a more reactive one can displace a less reactive one

  chlorine will displace bromine and iodine

  bromine will displace iodine but not chlorine

  iodine will not displace chlorine or bromine
• Uses of helium

  very low density used in balloons
• Uses of argon

  non flammable so used in lightbulbs
• uses of neon

  in advertising signs