atomic structure ༊*·˚ Flashcards
define an atom.
an atom is the smallest part of an element that can exist.
what are compounds formed from?
elements reacting in chemical reactions.
water is a compound. what is a compound?
2 or more elements chemically bonded together.
what is a mixture?
2 or more elements or compounds not chemically bonded together.
what does the law of conservation of mass state?
the law of conservation of mass states the total mass of the products formed in a reaction is equal to the total mass of reactants.
what are the symbols for the states of matter?
(s) solid (l) liquids (g) gases (aq) aqueous solutions.
mixtures can be separated by what five physical processes?
filtration, crystallisation, simple distillation, fractional distillation, and chromatography.
what substances is the process of filtration used to separate?
separates insoluble and soluble substances, the solid insoluble particles remain on the filter paper as residue.
what substances is the process of crystallisation used to separate?
separates soluble solids from a solution using evaporation. heating to remove the water, leaving he crystals behind.
what is a pure substance
pure substances contain one element / compound only.
what word describes liquids that dissolve in each other, mixing completely?
miscible.
in simple distillation, what two processes occur?
boiling and then condensing
how does chromatography separate substances in a mixture?
different boiling points.
what did JJ Thompson’s plum pudding model suggest the atom was?
the atom was a ball of positive charge with negative electrons embedded in it.
the results of the alpha particle scattering experiment led to what three conclusions?
- the mass of an atom was concentrated at the centre.
- there was empty space.
- electrons orbit the nucleus.
