chemistry topic 1- atomic structure and periodic table Flashcards
what is a molecule?
two or more atoms chemically joined
what happens as you go down the alkali metals?
they get more reactive
how are the groups arranged in the periodic table?
by atomic mass
what did Bohr discover?
electrons are contained in a shell
what is the charge of a proton?
+1
what is the charge of a neutron?
0
what is the charge of an electron?
-1
what is an element?
1 type of atom
what does chromatography separate?
substance dissolved in solvent
what does filtration separate?
solids, liquids and solutions
what does evaporation separate?
soluble solids dissolved in liquid
what does distillation separate?
2 or more different liquids
what do all acids have in them?
the H+ ion
what is a compound?
2 or more types of elements chemically joined
what did the plum pudding model show?
showed the atom as a ball of positive charge with electrons
what is an isotope?
elements with a different number of neutrons but the same number of protons
what does ductile mean?
when you stretch it gradually it will get thinner and become wire
what colour is bromine and what state is it?
red-brown
liquid
what colour is iodine and what state is it?
purple vapour
what colour is fluorine and what state is it?
yellow
gas
what colour is chlorine and what state is it?
green
gas
where are alkali metals
stored?
in oil
what are the characteristics of alkali metals?
-stored in oil
-indicator goes purple
-burst to flames in water
-get larger going down the group
-easy to cut
what happens when indicator is added to an alkali metal?
goes purple
what test is used to test for alkali metals?
squeaky pop
what are the characteristics of the group 7-halogens?
- non-metals
-reactivity decreases going down
what are the characteristics of the transition elements?
-good conductors of electricity
-opposite properties to group 1
-more dense
-hard
-low reactivity
what happens in the paper chromatography practical?
1)add a spot of ink to a line on filter paper with pencil
2)place in solvent and put lid on
3)solvent seeps up carrying ink
4)different dyes-different rates
5)take paper out and dry
6)pattern of results called a chromatogram
what happens in the filtration practical?
1)filter paper folded into a cone
2)mixture poured on top
3)solid is left in the filter paper
what happens in an evaporation practical?
1)pour the solution into an evaporating dish
2)slowly heat
3)solvent evaporates-eventually crystals form
what happens in a crystallisation practical?
1)pour solution into evaporating dish + heat
2)some of solvent will evaporate
3)remove from heat and leave to cool
4)salt should crystallize
what happens in fractional distillation?
1)put mixture in a flask + put fractioning column on top
2)different liquids evaporate at different temperatures
3)collect first liquid to evaporate and raise heat for the rest
what happens in simple distillation?
1)solution is heated-lowest boiling point evaporates first
2)vapour-cooled, condenses + collected
3)rest left in flask
who discovered electrons and in what year?
JJ Thompson
1897
who came up with the plum pudding model?
JJ Thompson
who conducted the alpha particle scattering experiment and came up with the nuclear model of the atom?
Rutherford
who proposed that electrons orbit the nucleus?
Bohr
who described atoms as a solid sphere?
John Dalton
how were the elements organised in the early 1800s?
by atomic weight
who left gaps and predicted new elements?
Dmitri Mendeleev
how are elements laid out on the modern periodic table?
in order of increasing atomic numbers
