C1 Atomic Structure Flashcards
What is everything made of? a_____
atoms
What is a compound?
Compounds are substances formed from 2 or more elements, the atoms of each are in fixed proportions throughout the compound and they’re held together by chemical bonds.
Two or more elements chemically bonded together in fixed proportions.
What is an atom
THe smallest particle we can break a substance into
What is a molecule?
more than one atom chemically bonded together
What is a mixture>
More than one substance (elements or compounds) present but not chemically bonded
In an atom the number of electrons is equal to the number of protons. True or false
true
Where is the mass in an atom concentrated
THe nucleus
Name the 4 state symbols
s= solid
l= liquid
g= gas
aq= aqueous
WHat is aqueous
WHen a solute is dissolved in a solvent of water
Explain a method for paper chromatography
-A spot of the mixture (pen ink) is placed on the bottom of the chromatography paper
-The chromatography paper is placed in the solvent (water)
-Solvent (water) soaks up through the paper
-THe different dyes in the ink will have different solubilities
-The more soluble the dye is, the further it will move up the paper
-THe picture is called a chromatogram
Why do you draw the start line of paper chromatography in pencil
PEncil marks are insoluble and won’t dissolve in the solvent
Explain why you would be able to collect a more concentrated sample of ethanol from a mixture of water and ethanol using fractional distillation than using simple distillation
In fractional distillation you separate the water and ethanol
-In simple distillation the water and ethanol are not separated.
-In simple they both end up in the condenser
-In fractional the water remains in the round bottom flask and the ethanol ends up in the condenser
What are the relative masses of:
-proton
-electron
-neutron
proton: 1
electron: 0
neutron: 1
What was the plum pudding model and who came up with it
JJ Thomson put forward a model that showed the atom as a ball of positive charge with electrons (plums) stuck inside
What experiment did Rutherford, Geiger and Marsden carry out?
Alpha particle scatterig experiments
How did Rutherford prove the plum pudding model wrong.
He fired positively charged alpha particles at an extremely thin sheet of gold. In the experiment they expected particles to pass straight through the sheet or be slightly deflected.
This was because it was thought that the positive charge of each atom was thought to be very spread out through the ‘pudding’ of the atom.
Most particles did go straight through, however more were deflected than expected.
A small number were deflected backwards so the plum pudding model couldn’t be correct.
THis is because some particles were deflected back by the nucleus but most went through the empty space of the atom.
He proved the existence of protons
What was Rutherford’s model
THe nuclear model.
He proposed that electrons must orbit the nucleus in a cloud and the nucleus contains dense positively charged protons. (no neutrons)
Why is the total mass of products formed in a reaction equal to the total mass of reactants?
Law of conservation of mass
What did Bohr discover
-There could be no dense cloud of electrons around the nucleus as Rutherford described as it would be attracted to the nucleus and cause the atom to collapse
What did Bohr propose
He proposed that electrons orbited the nucleus in fixed shells
-Each shell being a fixed distance from the nucleus
-His theory of atomic structure was supported by many experiments and helped many scientists’ observations of the time