C1 Atomic Structure Flashcards
What are all substances made out of?
Atoms and there around 100 of them
What is the name for substances made out of only one atom?
Elements
Where are all the elements and their symbols shown?
In the periodic table
What do the symbols represent?
The element/atom name
Where are the metals found on the table?
to the left side of the table where there is a staircase going from group 3-7
Where are non metals found?
On the right side
What are the elements in the table arranged into?
columns called periods
What are compounds?
Different types of atoms/elements bonded together
What are atoms made out of?
Nucleus containing protons and neutrons and electrons orbiting in shells on the edge of the atom.
What do chemical reactions show?
The reactants (the substances you start out with) and the product (the substance you end with)
What do symbol equations do that word equations don’t?
Let you see how much each element is involved.
What does it mean when the reaction is balanced?
There are the same amount of elements on both sides of the reaction
What is the Law of conservation of mass?
The total mass of the products formed in the reaction is equal to the total mass of the reactants.(mass cant be created or destroyed)
Why when Calcium Carbonate is heated it appears to lose mass even though the products are the same mass as the reactants.
When the reactant is heated carbon dioxide is given off and then the products look smaller as mass is loss when co2 is released.
What are the 4 state symbols to put next to the symbol name of the equations.
solid (s),liquid(l), gas(g),aqueous(aq) which means dissolved in water
What is a mixture?
2 or more elements not chemically bonded together
Differences between mixtures and compound
compounds have a fixed amount of atoms and have to be seperated using chemical reactions and are chemically bonded while mixtures dont have a fixed amount can be separated physically and have no chemical bonds.
4 means of seperating mixtures
chromatography fitration distillation crystallisation
What is filtration used for?
filtering insoluble particles from solvents-sand filtered from water using filter paper which let the water through but keeps sand in.
What is crystallisation used for ?
To extract a soluble particle (solute) from a solvent eg salt from seawater.This occurs by heating the solution until crystals occur on the evaporation dish then when it is a saturated solution leave the the dish to evaporate out naturally to form crystals of the solute.
What is simple distillation?
Simple Distillation is a separation technique used to separate a solvent from a mixture. For example, water can be separated from salt solution by distillation.
Simple Distillation involves boiling the mixture and then condensing the gas to produce a liquid. Simple Distillation is a separation technique used to separate liquid (the solvent) from a mixture and keep the liquid part. Distillation involves boiling the solution and then condensing the vapour back into a liquid by cooling it down.Eg.collecting both salt and water from sea water
Why is fractional distillation used differently from simple distillation and what is it?
Some mixtures contain more than one liquid. If there are two different liquids with different boiling points, they can also be separated using distillation.
Ethanol boils at 78°C, whereas water boils at 100°C. A mixture of ethanol and water can be separated using fractional distillation. Since ethanol has a higher boiling point most of the evaporate will come up the fractionating tower which gets cooler the higher. A thermometer should say (which is at the top) when the top reaches ethanol boiling point. Then ethanol will rise up condense into liquid and be collected in a flask while any water that gets evaporated off gets instantly condensed as it reaches the top and fall back down into the original flask.It is more commonly used for seperating liquids such as crude oil.
What is chromatography used for?
Paper chromatography is used to separate mixtures of soluble substances. These are often coloured substances such as food colourings, inks, dyes or plant pigments.
Explain the chromatography phases.
Chromatography relies on two different ‘phases’:
the stationary phase, which in paper chromatography is very uniform, absorbent paper
the mobile phase is the solvent that moves through the paper, carrying different substances with it
The different dissolved substances in a mixture are attracted to the two phases in different proportions. This causes them to move at different rates through the paper.
What do different results on a chromatogram show?
Separation by chromatography produces a chromatogram. A paper chromatogram can be used to distinguish between pure and impure substances:
a pure substance produces one spot on the chromatogram
an impure substance, or mixture, produces two or more spots.
How do you identify similar substance in a chromatogram.
A paper chromatogram can also be used to identify substances by comparing them with known substances. Two substances are likely to be the same if:
they produce the same number of spots, and these match in colour
the spots travel the same distance up the paper
Who discovered the idea of atoms?
John Dalton
How did JJ thompson discover the electron?
He was applying high voltages to gases in low pressure in a vacuum and he realised that the glass was glowing in the positive end which meant thousand of negative particles were attracted to the positive end of the tube so he theorized electrons.
What is the plum pudding model?
The model of atom where the atom was a sphere of positive charge dotted by negative electrons like plums in a pudding.
What was the evidence for the nucleus
Hans Geiger and Ernest Marsden, directed a beam of alpha particles at a very thin gold leaf suspended in a vacuum.The vacuum is important because any deflection of the alpha particles would only be because of collisions with the gold foil and not due to collisions with air particles.
Gold was used because it was the only metal that could be rolled out to be very, very thin without cracking.Since the gold foil was very thin, it was thought that the alpha particles could pass straight through it, or possibly puncture the foil. The scientists were very surprised when other things happened:
most of the alpha particles did pass straight through the foil
a small number of alpha particles were deflected by large angles (> 4°) as they passed through the foil
a very small number of alpha particles came straight back off the foil
The fact that most alpha particles went straight through the foil is evidence for the atom being mostly empty space.
A small number of alpha particles being deflected at large angles suggested that there is a concentration of positive charge in the atom. Like charges repel, so the positive alpha particles were being repelled by positive charges.
The very small number of alpha particles coming straight back suggested that the positive charge and mass are concentrated in a tiny volume in the atom (the nucleus). The tiny number of affected particles means the chance of being on that exact collision course was very small, therefore the ‘target’ being aimed at had to be equally tiny.
What did Niels Bohr discover?
He noticed when heating atoms only gave specific amounts of energy.He then theorized that electrons were orbiting at set distances unlike rutherford nuclear model which makes them move in not set distances.
Why were neutrons difficult to be discovered?
They have no charge therefore being undetectable.
What did James Chadwick discover
the proton
What are the two subatomic particles in the nucleus
Proton and Neutron
What are charges of the subatomic particles?
Proton +1
Neutron)
Electron-1
What are the masses of the different sa particles?
Proton 1
Neutron 1
Electron 1/1836
What is the atomic number?
The amount of protons
What is the mass number?
The number of protons and neutrons
How to find electrons using Atomic number
the electrons usually eill be the same amount.
What is an isotope
An atom with a various propotion of neutrons but has the same chemical propeties
how much electrons in each shell does in the first 20 elements
first 2
second 8
third 8
first 2
for example what if the configuration of element 17 chlorine
2 +8 +7 =17
so
2,8,7
for example what if the configuration of element 17 chlorine
2 +8 +7 =17
so
2,8,7
What do the group number and the number of electrons on the valence shell share?
Same number and elements in the group will have the same properties as the other elements in their group because the way an element reacts is based on the elements on the outer shell.
State 2 ways in which rutherford changed thomson’s model of the atom
positive charge concentrated into very small volume at
centre of atom (nucleus),
electrons orbit nucleus
How did bohr fix rutherfords model?
Energy emitted from electron transitions can only have
certain fixed energies,
so he refined the ‘orbiting electrons’ in Rutherford’s
nuclear model to ‘orbiting electrons in energy levels (or
shells) at fixed distances from the nucleus’.
