C2 the periodic table Flashcards
how are the elements arranged in the periodic table
in order of atomic number and so that elements with similar properties are in group
Elements in the same group in the periodic table have the same
number of electrons in their outer shell
how was the periodic table arranged before the discovery of protons electrons and neutrons
in order of their atomic weight
how did Mendeleev organize the periodic table
leaving gaps for elements that he thought had not been discovered (Elements with properties predicted by Mendeleev were discovered)
organized elements in increasing atomic number
what are metals
elements that react to form positive ions
what are non metals
elements that do not form positive ions
what is group 0
the noble gases
describe the electronic structure of group 0 elements
They are unreactive and do not easily form molecules
because their atoms have stable arrangements of electrons. The
noble gases have eight electrons in their outer shell, except for
helium, which has only two electrons
what are the trends in group 0
The boiling points of the noble gases increase going down the group
what is group 1
the alkali metals
describe the electronic structure of group 1 elements
1 electron in the outer shell
what trends are in group 1
melting and boiling point decrease going down the group
more reactive down the group
how are alkalis stored
under oil because they react very vigorously with oxygen and water
what happens when alkalis react with water
a metal hydroxide id formed and hydrogen gas is given off
what happens when lithium is added to water
When lithium is added to water, lithium floats. It fizzes steadily and becomes smaller, until it eventually disappears.
what happens when sodium is added to water
When sodium is added to water, the sodium melts to form a ball that moves around on the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.
