topic 1

• what is the relative mass and charge of a proton?

  relative mass: 1 charge: +1
• whats the relative mass and charge of an electron?

  relative mass : very small

  charge : -1
• what’s the relative mass and charge of a neutron?

  relative mass: 1 charge : 0
• what is an isotope?

  an isotope is a variant of an element that has the same number of protons but a different number of neutrons in its nucleus. it has the same atomic number but a different mass number
• what is a mixture?


  a combination of two or more substances that are not chemically bonded. the elements are easy to separate
• what is simple distillation?

  separating a liquid from a solution

  
• what is fractional distillation?

  separating out a mixture of liquids

  can be used to separate out crude oil into fractions
• what are the properties of alkali metals(group 1)?

  •low melting and boiling points

  •soft + very reactive

  •low density

  •get more reactive as u go down

  >they get bigger so it’s easier to lose an electron

  •form ionic compounds with non metals

  •react with water to produce hydrogen

  •they react with a chlorine to produce a metal salt

  •react with oxygen to form metal oxides
• what are the properties of halogens(group 7)?

  •non metals

  •become less reactive as u go down

  >harder to gain an electron due to distance from the nucleus

  •melting and boiling points become higher as u go down
• what are the properties of the noble gases(group 0)?

  •unreactive due to full outer shells

  •stable due to full outer shells

  •colourless gases at room temperature

  •boiling point increases as u go down

  >greater intermolecular forces due to more electrons

  •helium, neon, argon
• what are the halogens?


  •fluorine, chlorine, bromine, iodine
• what is the plum pudding model of the atom?

  •thomson in 1897

  •ball of positive mass with electrons embedded
• what is the alpha particle scattering experiment?

  •rutherford in 1909

  •most passed thru = atom mostly empty space

  •some reflected from centre = mass concentrated at centre + nucleus is charged
• what did niels bohr discover about the atom?

  •electrons oribit in shells

  •1911
• what did james chadwick discover about the atom?

  •nucleus contained neutrons

  •1940
• what is chromatography?

  separating out mixtures
• what is filtration?

  separating solids from liquids
• what is evaporation?

  •separating soluble salt from solution

  •quick way
• what is crystallisation?

  •separating soluble salt from solution

  •slower method