C1 - Atomic Structure and the Periodic Table

Question 1

How big is an atom?

Answer 1

1 X 10^-10

Question 2

State five facts about the nucleus.

Answer 2

1) It’s in the middle of the atom.
2) It contains protons and neutrons.
3) The nucleus has a radius of 1 X 10^-14 (1/10,000 of the radius of an atom).
4) It has a positive charge (because of the protons).
5) Almost all of the mass of an atom is found in the nucleus.

Question 3

What is the mass, charge and position of protons, neutrons and electrons?

Answer 3

Protons - 1g, +1, nucleus.
Neutrons - 1g, 0, nucleus.
Electrons - 0 or negligible, -1, energy levels.

Question 4

How do you calculate the amount of neutrons in an atom?

Answer 4

Subtract the atomic number from the mass number.

Question 5

What is an element?

Answer 5

A substance made up of the same atoms.

Question 6

Elements consist of atoms with the same?

Answer 6

Atomic number.

Question 7

What is an isotope?

Answer 7

They have the same number of protons, but a different number of neutrons. This means that they have the same atomic number but different mass numbers.

Question 8

How do you calculate relative atomic mass?

Answer 8

Sum of (isotope abundance X isotope mass number)
———————————————————
Sum of abundances of all the isotopes

Question 9

What is a compound?

Answer 9

Substances made up of two or more elements and are held together by chemical bonds.

Question 10

What does a compound which is formed from a metal and non metal consist of?

Answer 10

Positive and negative ions which have a strong electrostatic force of attraction between each other.

Question 11

What do chemical equations show?

Answer 11

Chemical changes.

Question 12

What is a mixture?

Answer 12

A group of substances that aren’t chemically bonded together.

Question 13

What is chromatography used for?

Answer 13

Separating different dyes in an ink.

Question 14

Describe the chromatography practical.

Answer 14

1) Draw a base line near the bottom of a sheet of chromatography paper. This must be done in pencil so it doesn’t dissolve in the solvent.
2) Add a spot of ink to the base line and place the sheet in a beaker of solvent (such as water).
3) Make sure the base line doesn’t touch the solvent so the ink doesn’t dissolve into it.
4) Place a lid on top of the container to stop the solvent evaporating.
5) The solvent should then seep up the paper, carrying ink with it.
6) If a dye is insoluble, it will stay on the base line. This is because the more soluble the dye, the further up the paper it moves.
7) When the solvent has nearly reached the top of the paper, take the paper out and leave it to dry.
8) The end result is called a chromatogram.

Question 15

What does filtration separate?

Answer 15

Insoluble solids from liquids.

Question 16

Describe filtration.

Answer 16

1) Fold the filter paper into a cone shape.
2) Place the filter paper into a funnel.
3) Place the funnel into a beaker.
4) Pour the mixture into the funnel.
5) The insoluble solid wouldn’t flow down the tube, so it is separated from the liquid.

Question 17

Describe how to separate soluble solids.

Answer 17

1) Pour the solution into an evaporating dish.
2) Slowly heat the solution until crystals start to form.
3) Heat the solution or allow the solution to dry off until all you have left is dry crystals.

Question 18

What is simple distillation used for?

Answer 18

To separate solutions.

Question 19

Describe simple distillation.

Answer 19

1) The solution is slowly heated. The part of the solution that has the lowest boiling point will evaporate first.
2) The vapour then travels through a condenser where it cools, condenses and is collected.
3) The rest of the solution would remain in the flask.

Question 20

What is the problem with simple distillation?

Answer 20

You can only use it to separate solutions with very different boiling points.

Question 21

What is fractional distillation used for?

Answer 21

Separate mixtures of liquids with similar boiling points.

Question 22

Describe fractional distillation.

Answer 22

1) Pour your mixture into a flask and stick a fractionating column on top. Then heat the flask.
2) The liquids will have different boiling points, so they will evaporate at different temperatures.
3) The liquid with the lowest boiling point evaporates first. When the temperature reaches this point, the liquid will reach the top of the column.
4) Liquids with higher boiling points may also begin to evaporate, but the column is cooler towards the top so they will only get part of the way up before condensing and going back to the bottom of the flask.
5) When the first liquid has been collected, raise the temperature until the next one reaches the the top.

Question 23

How did John Dalton describe atoms?

Answer 23

Atoms were solid spheres and different spheres made up the different elements.

Question 24

Who created the plum pudding model and what is it?

Answer 24

• JJ Thomson
• The atom was described as a ball of positive charge with negative electrons embedded in it.

Question 25

Who conducted the alpha scattering experiment and what was it?

Answer 25

- Ernest Rutherford. - Positive alpha particles were fired at an extremely thin sheet of gold.

Question 26

What discoveries were made about the atom after the alpha scattering experiment?

Answer 26

- Most atoms went straight through the the gold sheet, so it showed that atoms were made up of mostly empty space. - Some particles were deflected, so there was a positive mass in the atom. - One particle deflected backwards, so the positive mass was very, very small.

Question 27

What did Niels Bohr discover?

Answer 27

Energy levels. Electrons orbited the nucleus in these fixed shells that were a fixed distance away from the nucleus.

Question 28

How were protons and neutrons discovered?

Answer 28

- Further experiments by Rutherford showed that the nucleus could be divided into smaller particles. These were called protons. - James Chadwick carried out experiments to prove the existence of neutral particles, known as neutrons.

Question 29

How were elements arranged before?

Answer 29

1) Physical and chemical properties. 2) Atomic Weight.

Question 30

How did Mendeleev arrange elements?

Answer 30

1) He left gaps. This allowed him to predict the properties of undiscovered elements such as Gallium. 2) He arranged them both in order of atomic weight and properties, so he swapped a few elements when arranging them.

Question 31

Where are metals and non-metals found on the periodic table?

Answer 31

Metals are found on the right whereas non-metals are found on the left.

Question 32

What are the properties of metals and non-metals?

Answer 32

Metals: - Strong - Malleable - Conductors of heat and electricity - High melting and boiling points - Lustrous - Higher density Non-metals: - Weak - Brittle - Don’t conduct heat and electricity - Dull - Lower density

Question 33

What are the special properties of transitional metals?

Answer 33

- Have more than one ion. - Often make coloured compounds. - Make good catalysts.

Question 34

What are Group 1 metals known as?

Answer 34

Alkali metals.

Question 35

Why are Group 1 metals very reactive?

Answer 35

They only have one electron in their outer shell.

Question 36

What are the trends for Group 1 elements as you move down the group?

Answer 36

1) Reactivity increases because the outer electron is more easily lost because the electrostatic force of attraction between the nucleus and electron decreases. 2) Lower melting and boiling points. 3) Higher relative atomic mass.

Question 37

How do group 1 metals react with water?

Answer 37

- Vigorously - Produce hydrogen gas - Potassium —> flame

Question 38

What are the differences between alkali metals and transitional metals?

Answer 38

- More reactive. - Less dense. - Weaker. - Soft. - Lower boiling/melting points.

Question 39

What is the trend in Group 7 elements as you move down the group?

Answer 39

- Less reactive. - Higher melting and boiling points. - Higher relative atomic mass.

Question 40

Why are Group 0 elements inert?

Answer 40

They have a stable electronic configuration, so they don’t have to react.

Question 41

What is the trend in Group 0 as you move down the group?

Answer 41

Boiling points increase because there are more electrons so there are stronger intermolecular forces which require more energy to overcome.