atomic structure and the periodic table

• What is an atom


  An atom is the smallest part of an element that can exist
• What does the Nucleus contain? what is its overall charge

  contains protons and neutrons and has an overall positive charge
• what is the relative mass of a proton

  1
• what is the relative mass of a neutron

  1
• what is the relative mass of an electron

  almost 0
• what do the number of protons equal to?

  the number of electrons
• what is the charge of an atom

  no overall charge (protons = electrons)
• what is the atomic number and is it the big number or small number?

  tells you how many protons there are, it is the small number
• what is the atomic mass and is it the big or small number?

  tells you the total number of protons and neutrons, it is always the big number
• What is an element


  an element is a substance that is made up of atoms that have the same number of protons in their nucleus.
• What does the number of protons determine?

  what type of atom is is e.g ( hydrogen has 1 and helium has 2)
• What are isotopes?

  different forms of the same element which have the same number of protons but different number of neutrons (e.g carbon-12 and carbon-13)
• What is the relative atomic mass?

  An average mass taking into account the different masses and abundances
• what is the formula for relative atomic mass?

  sum of (isotope abundance x isotope mass number) ---------------------------------------------------------------------- sum of abundances of all isotopes
• what are compounds?

  formed from two or more elements chemically bonded together
• how do you make chemical bonds?

  it involves giving away, taking or sharing electrons
• what is an ion?

  a charged particle
• what is ionic bonding?

  when non metals and metals bond
• what is covalent bonding?

  bonding between two non - metals
• how can compounds be seperated?

  from chemical reactions
• how are chemical reactions represented?

  Chemical reactions can be represented by word equations or equations using symbols and formulae.
• What are Mixtures?

  consists of two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged.
• How can mixtures be seperated?

  Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions and no new substances are made.
• what are 2 examples of mixtures?

  air and crude oil
• Why do u not use a pen in Chromatography?

  because a pen would smudge from the water
• What does filtration do?

  Seperates insoluble solids from liquids
• What are the two ways to seperate soluble solids from solutions?

  evaporation and crystallisation
• 2 ways to seperate rock salt

  crystallisation and filtiration
• what is distillation used for ?

  to seperate a liquid from a solution
• what is fractional distillation used for?

  to seperate a mixture of liquids
• what did the discovery of the electron lead to?

  Rutherfords plum pudding model
• what did the plum pudding model suggest?

  The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it.
• what did the alpha particle scattering conclude?

  led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged. This nuclear model replaced the plum pudding model.
• Who invented the nucleur model

  Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances
• why did Mendeleev leave gaps in his tables of elements

  to leave space for elements that had not been found out
• How were elements arranged in the early 1800s?

  by atomic mass
• how are elements arranged in groups?

  in order of atomic (proton) number so the elements with similar properties are in columns
• How do we know that elements in the same group habe similar chemical properties

  because it has the same number of electrons in its outer shell
• what are the group 7 elements called?

  Halogens
• what is the appearance of halogens and are they metals?

  non metals with coloured vapours