Atomic structure and the periodic table Flashcards
(34 cards)
what is in the nucleus ?
protons and neutrons
what is the charge of the nucleus ?
POSITIVE
what is the relationship between protons and electrons in an ATOM?
they are the same
same number of protons and electrons
what is the atomic number ?
how many protons
what is the mass number?
total number of protons and neutrons
what determines what the element is?
the number of protons in the nucleus
what is an isotope ?
different forms of the same elements
same number of protons
different numbers of neutrons
what is the formula for relative atomic mass?
(isotope abundance x isotope mass number) / sum of all the isotopes
what is a compound?
atoms joined together ( two or more)
METAL + NON-METAL
ionic binding
ions
NON-METAL + NON- METAL
covalent bonding
molecules
method of chromatography?
- filter paper with a line drawn IN PENCIL
- draw a pot of ink on line
- place the filter paper in a beaker with water or a solvent ( UNDER ink sample)
- place lid (stop evaporation)
- wait 15 minutes till ink separates out and solvent has moved up the filter paper
what is filtration used for?
insoluble solids and liquids
method for crystallisation?
- pour solution into evaporating basin
- gently heat over a bunsen burner
- when you can see crystals start to form remove from heat
- let the rest evaporate in root temperature
- pat dry
MAIN STEPS for crystallisation:
DISSOLVE
FILTER
EVAPORATE
what is distillation used for?
to separate out solutions
eg. pure water from sea water
- uses a condenser, thermometer, bunsen
who created the idea of the plum pudding model?
THOMSON
who conducted the alpha particle scattering experiment?
RUTHERFORD
what did the alpha particle scattering experiment lead to?
discovery of the NUCLEUS
who suggested that electrons were contained in shells?
BOHR
who discovered neutrons?
CHADWICK
how were atoms arranged in the 1800’s?
by atomic mass
what was Mendeleev’s periodic table like?
- had gaps (to make predictions and leave room for undiscovered elements)
- even though it was organised by atomic mass it grouped similar properties together
what is a column on the modern periodic table?
elements with similar properties