C2 the periodic table Flashcards
how were elements categorised in the early 1800s
by their physical and chemical properties and their atomic weight
when did dmitri mendeleev make his table of elements
1867
how did mendeleev organise his table of elements
he mainly organised them in order of atomic weight and left gaps for undiscovered elements
how is the modern periodic table organised
increasing atom number (proton number)
which side are metals and non metals on
non metals are to the right and metals are to the left
what are groups
the vertical columns that’s tell u how many electrons there are in the outer shell
what is a metal
an element that can form positive ions when they react
why do atoms react
to form a full outer shell by losing gaining or sharing electrons
what properties do metals have
have metallic bonding- strong, conduct heat and electricity, high boiling and melting points
what properties do non metals have
brittle, aren’t always solids at room temp, don’t generally conduct electricity and often have lower density
group 1 elements
alkali metals, soft and reactive, form ionic compounds with non-metals, increasing reactivity as you go down, lower melting and boiling points
group 7 elements
halogens- non metals with coloured vapours, as u go down they become less reactive and have higher melting and boiling points, form molecular compounds
fluorine
very reactive, poisonous yellow gas
chlorine
fairly reactive poisonous green gas
bromine
dense, poisonous red-brown volatile liquid
