Periodic Table Flashcards
when was Dalton and what was his discovery?
start of 19th century - atoms were described as solid spheres
when was Thompson and what was his discovery?
1897 - an atom is a ball of charge, electrons are scattered
when was Rutherford and what was his discovery?
1909 - alpha particles scattering, mass is concentrated at the centre, the nucleus has a charge, most atoms are empty space
when was Bohr and what was his discovery?
1911 - electrons are in shells orbiting the nucleus
when was chadwick and what was his discovery?
1940 - there are neutrons in the nucleus
how did Mendeleev organise the periodic table?
order of atomic mass but left some gaps
what is the periodic table now in order of?
atomic mass/proton number
where are the metals located and what are their properties?
left - strong, malleable, good conductors of electricity and heat, bond metallically
where are the non-metals located and what are their properties?
right - dull, brittle, always a solid at room temperature
what are group 7 elements called and what are their properties?
halogens - less reactive as you go down, hard to gain extra electrons (outer shell is further from the nucleus), melting and boiling points become higher
what are group 0 elements called and what are their properties?
noble gases - unreactive as they have full outer shells, very stable, all colourless at room temperature, boiling points increase and you go down, strong intermolecular forces
what are group 1 elements called and what are their properties?
alkali metals - soft, very reactive (one electron in outer shell), low density, easier to lose an electron that is further from the nucleus
when does an element become an ion?
when is loses or gains electrons
what is an ion?
and charged particle that can be positive or negative
what happens to the metal?
loses electrons to become positively charged
what happens to the non-metal?
gain an electron becoming negatively charged
