periodic table! Flashcards
what is the alkali metals
group 1
what are the halogens?
group 7
what are the noble gases
group 0
what is the trend in group 1
the atoms get bigger and the number of the electron shells between the nucleus and the outer shell electrons increase as you go down group 1
what is the trend in group 7
going down group 7, the melting and boiling points increase.
what is the trend im group 0
the boiling point increases as you go down the group
what is the Bohr Model
1913
it explains how electrons orbit the nucleus at fixed energy levels
what is the plum pudding model about
1897
it is the scientific idea that an atom is a sphere of positive charge, with negatively charged electrons in it.
who discovered the nucleus and in what year?
Rutherford and 1911
who discovered the neutron and in what year?
James Chadwick in 1932
feautues of group 1 metals
- soft
- they tarnish
- the reactivity increases as you go down the group
- the melting and boiling points increase
feauture of group 7 metals
- the element get darker as you go down the group
- they go from gas, to liquid, to solid.
- the reactivity decrease as you go down the group
colours of the halogens
- chlorine: green gas
- bromine: red/ brown liquid
- iodine: purple soild
how are the elements arranged in Newlands periodic table?
they are arranged by atomic weight/ number
why did other scientists disagree?
because there were two elements in the same group
