Flashcards in topic 1 (atomic structure..) Deck (21)
an atom is a very small thing
a single type of atom
2 or more elements that are chemically combined
2 or more elements that are not chemically combined
involves separation of a solvent and solid (pen dots on a piece of paper)
A method of separating mixtures based on differences in their volatilities in a boiling liquid mixture.
Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize.
separate soluble salt from solution
separating a liquid and a solid
electron energy levels
a specific number of electrons go on each shell
alpha scattering experiment
In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. But a few were scattered in different directions. This evidence led Rutherford to suggest a new model for the atom, called the nuclear model
the plum pudding model
this suggested the atom was a ball of positive charge with negative electrons embedded in it
the nuclear model
niels Bohr explained electrons orbit the nucleus at fixed distances
the positive charge is due to protons
James Chadwick explains nucleus contains neutrons
is the number of protons/electrons in an atom
mass number or atomic mass
is the number of protons plus neutrons in an atom
the early periodic table in 1800s were arranged by atomic mass
Mendeleev did take the elements properties into count
Mendeleev left gaps and predicted new elements
properties of transition metals
high melting points.
they form coloured compounds.
they (and their compounds) can act as catalysts.
group 0 elements
The group 0 elements, the noble gases, are all unreactive non-metal gases. They show trends in their physical properties.
All group 0 noble gases have eight electrons in the full outer shell, except helium just has the two, but still a full shell! The melting point of group 0 noble gases increases down the group. The boiling point of group 0 noble gases increases down the group.
group 1 elements
Alkali metals are grey solids with shiny silvery surfaces when freshly cut.
These surfaces turn dull when exposed to air.This is because alkali metals are very reactive.
They react rapidly with oxygen and water vapour in the air when exposed.
melting and boiling points decrease as you go down the group
group 7 elements
The halogens have low melting points and low boiling points.
they are diatomic molecules (meaning they come in two's)
they are highly reactive (mostly at the top)
increase in boiling point as you go down
used in sterilisation