atoms and the periodic table

atoms and the periodic table

1. mendeleev

   • arranged elements in order of relative atomic mass

2. atom structure

   • nucleus of protons and neutrons, and surrounded by electrons
     • neutrons dont have a charge, so the nucleus of an atom is always positively charged
     • has same number of electrons as protons = overall neutral
     • protons and neutrons have same mass, electrons are teenie tinie
     • atomic number = proton number
     • mass number = total number of protons and neutrons
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     • relative atomic mass = mass of an atom relative to that of carbon

3. isotopes have same number as protons as elements but different neutrons