the periodic table Flashcards
(23 cards)
how did newlands organise the elements?
by their weight
what problem did newlands ordering of the elements have?
he assumed that all the elements had been discovered and arranged them with different reactivities
what did mendeleev do to re-organise the elements?
he arranged them by weight but made sure they were similar reactions and left gaps
why were the noble gases not discovered until later?
because they are colourless, odourless, and unreactive
how are elements in the modern periodic table ordered?
atomic number
what is group 0 of the periodic table?
noble gases
what are characteristics of noble gases? (4)
stable
unreactive
don’t bond with other elements
monotomic (exist as individual atoms)
why are noble gases unreactive?
they all have a full outer shell of electrons and do not need to gain, lose or share electrons to form chemical bonds
what is the trend in density as you move down group 0?
gets denser as you move down the group
what is produced when metals react with water?
hydrogen gas is produced
what is group 1 of the periodic table?
alkali metals
what are the physical propertied of lithium? (3)
shiny
malleable
low density- floats on water
what are the physical propertied of sodium? (5)
shiny
malleable
low density- floats on water
easy to cut
quickly tarnished
what are the physical propertied of potassium?
soft
not shiny
low desnity- floats on water
what is the reaction of lithium with water? (2)
fizzes
moves around
what is the reaction of sodium with water? (4)
fizzes
sizzles
lots of bubbles
forms a ball
what is the reaction of potassium with water? (4)
purple flame
fizzes
bubbles
moves
what happens to reactivity as you move down group 1?
increases
why is potassium more reactive than lithium?
the negative electron in the outer shell is further away from the positive nucleus in pottasium than lithium
what happens as you go down group 7?
density, melting and boiling points all increase (reactivity decreases)
what are transition metals?
elements that are metals and have typical metallic properties
what are transition elements and its compound?
catalysts
what is a mole?
an amount of a substance
