unit 2: the periodic table Flashcards
what are group numbers based on?
the number of electrons in the elements outer shell
describe and explain the difference between sodium and potassium in their reactivity with water
-both sodium and potassium will fizz and move around in water
-potassium forms lilac flames but sodium doesn’t
-potassium is more reactive in water than sodium because due to the element being further down in group 1 meaning its more reactive as the outer shells is further away so the electrostatic force between protons and electrons is weaker
which group 7 element is solid at room temp?
iodine
what would happen when iodine is added to potassium bromide?
no reaction because iodine is less reactive than bromine meaning iodine is unable to displace it
why do the elements in group 0 exist as single atoms?
-because they have full outer shells
-they don’t combine
how was mendeleev’s table an improvement from newlands’ table?
- elements were seperated into groups and periods
-he left gaps for future scientific discovery
mass number
sum of neutrons and protons in an element
atomic number
the number of protons in an element
what are the order of elements in the periodic table based on?
to ensure they are in groups with elements that all share similar properties
how was the periodic table orginally ordered by?
-atomic weight
the discovery of isotopes led to…
the realisation that ordering elements based on atomic weight would not always be correct
difference between non metals and metals
-elements that react to form positive ions are metals and elements that do not are non metals
where are metals located on the periodic table?
- at the left toward the bottom
where are non metals located on the periodic table?
at the right toward the top
group 0 elements are called
the noble gases
