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
group 0 elements are…
- unreactive
- do not easily form molecules because of their stable arrangement of electrons
- they all have full outer shells aside from helium which only has 2 electrons on its outershell
as you go down the group 0
the boiling points increase
group 1
alkali metals
group 1 elements have…
-1 electron on its outer shell
- as a result they have characteristic properties
group 7
halogens
group 7 elements have…
- 7 electrons on its outer shell
-they are non metals
as you go down group 7…
-the melting point and boiling point increases
- the reactivity decreases
a more reactive halogen can..
displace a less reactive halogen
