Paper 1 - Topic 1, Atomic Structure And The Periodic Table Flashcards

1
Q

Describe the nucleus

A
  • In the middle of the atom
  • Contains protons and neutrons
  • Has a positive charge (because of protons)
  • Almost the whole mass is concentrated in the nucleus
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2
Q

Describe Electrons

A
  • Move around the nucleus in electron shells
  • They’re negatively charged and tiny
  • Electrons have virtually no mass
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3
Q

Why is an atoms overall charge neutral

A
  • they have the same number of protons as electrons
  • the charge on the electrons is the same size as the charge on protons, the charges cancel each other out
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4
Q

What does the atomic number tell you

A

How many protons there are in

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5
Q

What does the mass number tell you

A

The total number of protons and neutrons in the atom

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6
Q

How do you work out the number of neutrons

A

Mass number - atomic number

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7
Q

What is an isotope

A

Isotopes are different forms of the same element, which have the same number of protons but a different number of neutrons (same atomic number but different mass number)

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8
Q

What is the relative atomic mass (Ar)

A

An average mass taking into account the different masses and abundances of all isotopes that make up an element

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9
Q

What is the formula for relative atomic mass

A

Sum of (isotope abundance x isotope mass number)
—————————————————————————
sum of abundance of all the isotopes

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10
Q

What is a compound

A
  • Substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and held together by chemical bonds
  • usually difficult to separate the original elements of a compound out again - need a chemical reaction
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11
Q

What is ionic bonding

A
  • Compound which is formed from a metal and a non-metal
  • metal atoms lose electrons to form positive ions
  • non-metal atoms gain electrons to form negative ions
  • the opposite charges mean that the ions are strongly attracted to each other
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12
Q

What is covalent bonding

A
  • a compound formed from non-metals consists of molecules
  • each atom shares an electron with another atom
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13
Q

What is the formula for ammonia

A

NH3

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14
Q

What is the formula for sodium chloride

A

NaCl

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15
Q

What is the formula for carbon monoxide

A

CO

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16
Q

What is the formula for Hydrochloric acid

A

HCl

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17
Q

What is the formula for calcium chloride

A

CaCl2

18
Q

What is the formula for sodium carbonate

A

Na2CO3

19
Q

What is the formula for sulfuric acid

A

H2SO4

20
Q

What is the definition of mixture

A

A mixture is made from two or more elements or compounds being mixed together, without the formation of any chemical bonds. They can be separated using techniques like filtration, crystallisation, simple distillation, fractional distillation and chromatography

21
Q

How do you do paper chromatography

A
  1. Draw a line near the bottom of a sheet of filter paper (use a pencil as pencil is insoluble and won’t dissolve)
  2. Add a spot of ink to the line and place the sheet in a beaker of solvent (eg water or ethanol)
  3. Make sure the ink isn’t touching the solvent (as it will dissolve into it)
  4. Solvent seeps up the paper, carrying the ink with it
  5. Each different dye will move up the paper at a different rate and dyes will separate out
  6. If any dyes are insoluble it will stay at the baseline
  7. When solvent has reached top of paper, take paper out of beaker and leave to dry
22
Q

What does filtration separate

A

Insoluble solids from liquids

23
Q

How do you do filtration

A
  1. Pour the mixture into a filter funnel lined with filter paper with a beaker underneath
  2. The solid with get left behind in the filter paper while the liquid passes through
24
Q

What are two ways you can separate soluble solids from solutions

A

Evaporation and Crystallisation

25
Q

How do you do Evaporation

A
  1. Pour the solution into an evaporation dish
  2. Slowly heat the solution, the solvent will evaporate and the solution will get more concentrated. Eventually, crystals will start to form
  3. Keep heating the evaporating dish until all you have left are dry crystals
26
Q

How do you do crystallisation

A
  1. Pour the solution into an evaporating and gently heat the solution, some of the solvent will evaporate and the solution will get more concentrated
  2. Once solvent has evaporated or crystals start to form, remove dish from heat and leave to cool
  3. The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution
  4. Filter crystals out of solution and leave in warm place to dry
27
Q

What is simple distillation used for

A

To separate out a liquid from a solution

28
Q

What equipment is needed for simple distillation

A
  • clamp and stand
  • distillation flask
  • thermometer
  • Bunsen burner
  • condenser
  • receiving flask
29
Q

How do you do simple distillation

A
  1. Solution is heated. The part of the solution with the lowest boiling point will evaporate first
  2. Vapour is then cooled, condenses and turns back to a liquid
  3. Rest of solution is left behind in the flask
30
Q

What is the problem with simple distillation

A

Can only use to separate things with very different boiling points. If the boiling point goes higher than the boiling point of the substance with the higher boiling point, they will mix again

31
Q

If you have a mixture with similar boiling points, what method should you use

A

Fractional distillation

32
Q

How do you do fractional distillation

A
  1. Put mixture in a flask and put fractionating column on top, then you heat it
  2. Different liquids will have different boiling points so they will evaporate at different temperatures
  3. The liquid with the lowest boiling point will evaporate first, when the temp of the thermometer matches b.p of this liquid, it will reach top of column
  4. Liquids with higher b.p may start to evaporate but the column is cooler towards the top, so they will only get so far up before they condense
  5. When the first liquid has been collected, you raise the temp until the next one reaches the top
33
Q

How did John Dalton describe the atom in the 19th century

A

He described them as solid spheres and that different spheres made up different elements

34
Q

What did JJ Thomson conclude about his experiments

A
  • atoms weren’t solid spheres
  • his measurements of charge and mass showed that an atom must contain even smaller negative particles - electrons
  • he created the plum pudding model
35
Q

What did the plum pudding model show

A

Showed the atom as a ball of positive charge with electrons stuck in it

36
Q

Which experiment did Ernest Rutherford conduct

A
  • Fired alpha particles at a very thin sheet of gold.
  • He expected the particles to pass straight through or be slightly deflected because of the positive charge of each atom was thought to be spread out.
  • Whilst most particles went straight through, more were deflected than expected so plum pudding couldn’t be correct
37
Q

Which model did Rutherford create

A
  • the nuclear model
  • this model had a tiny positively charged nucleus in the centre
  • had a cloud of negative electrons surrounded the nucleus - most of atom is empty space
38
Q

What was the problem with Rutherford nuclear model

A

That the ‘cloud’ of electrons would be attracted to the nucleus and would cause atom to collapse

39
Q

What did Neil Bohr’s nuclear model suggest

A

That all electrons were in fixed shells and orbited the nucleus and each shell is a fixed distance from nucleus

40
Q

What did further experiments from Rutherford and others show

A

That the nucleus could be divided into smaller particles called protons which had a small amount of positive charge

41
Q

What did James Chadwick discover in 1932

A
  • carried out an experiment which provided evidence for neutral particles in the nucleus called neutrons
42
Q

Before the discovery of protons, neutrons and electrons, how were elements in the periodic table organised

A

By their atomic weights (relative atomic mass)