c1 - atomic structure and the periodic table

Question 1

what is an element?

Answer 1

a substance made up of one atom only

Question 2

what is a compound?

Answer 2

contain 2 or more different elements chemically combined together

Question 3

what is a mixture?

Answer 3

different elements or compounds not
chemically combined together

Question 4

what is a molecule?

Answer 4

A molecule has any elements chemically joined

Question 5

what is filtration?

Answer 5

it separates an insoluble (does not dissolve) solid from a liquid

Question 6

filtration method

Answer 6

1. Put the filter paper into the filter funnel
2. Pour the liquid in
3. The silver chloride (solid) will be collected in the filter paper
4. The water will pass through and will be collected in the beaker

Question 7

what is crystallisation?

Answer 7

To separate an soluble (does dissolve) solid from a liquid

Question 8

crystallisation method

Answer 8

1. put a heatproof mat down and the Bunsen burner above it
2. put the tripod on top and the gauze on the tripod.
3. place the evaporating basin on top of the gauze
4. pour the mixture into the evaporating basin and heat the Bunsen burner.
5. Water will evaporate and the soluble will crystalise in the basin.

Question 9

what is chromatography?

Answer 9

it is when you separate ink dyes based on solubility

Question 10

chromatography method

Answer 10

1. draw a pencil line on the filter paper and put ink colours on it
2. place the filter paper into a beaker of water (the solvent) below the pencil line
3. the solvent will rise up the paper revealing the soluble and insoluble colours.

mobile phase= solvent (moves up the paper)
stationary= paper (stays still)

Question 11

why do we draw the starting pencil line?

Answer 11

If we drew the line in pen, the pen ink would move up the paper, it would smudge - mix in with the results.

Question 12

what is simple distillation?

Answer 12

To separate a liquid from a solid if we want to keep the the liquid.

Question 13

simple distillation method

Answer 13

1. Heat the solution using a Bunsen burner
2. As we heat the liquid it starts to evaporate into a vapour
3. The vapor rises up the glass tube
4. The vapor now passes into the condenser
   (the condenser is kept cold by passing cold water through it)
5. The vapor now condenses into a liquid
6. We collect the liquid in our beaker

result:
We are left with crystals of the solid in the flask and the liquid in the beaker

We can use simple distillation to produce drinking water from sea water HOWEVER a lot of energy is needed.

Question 14

what is fractional distillation?

Answer 14

• To separate a mixture of different liquids
• These liquids must have different boiling points

Question 15

fractional distillation method

Answer 15

1. Heat the mixture using a Bunsen burner
2. As we heat the liquids they start to evaporate but the one with the lower boiling point will evaporate more easily.
3. When vapor rises (contains both liquid vapors) it enters the fractionating column
4. They then condense and drip back into the flask

Note: If the 2 liquids have got very similar boiling points, then it is much harder to separate them. We might need to carry out several rounds of fractional distillation.

Question 16

plum pudding model

Answer 16

JJ Thompson
a ball of positive charge with negative electrons scattered inside of it

Question 17

who did the alpha scattering experiment

Answer 17

Rutherford and Marsden

Question 18

results of alpha scattering experiment

Answer 18

the alpha
particles bounced
straight back - The centre of the
atom contains the most mass.

Some deflected slightly - The centre of the atom has a positive charge

Most of the alpha particles passed straight through - most of the atom is empty space

Question 19

what did Niels Bohr discover?

Answer 19

Electrons orbit the nucleus at specific distances.

Orbits are now called energy levels.

Question 20

what did James Chadwick discover?

Answer 20

The nucleus contains neutral particles called neutrons.

Question 21

order of discovery for subatomic molecules

Answer 21

electrons
proton
neutron

Question 22

radius of atom

Answer 22

0.1nm

1 x 10^10m

Question 23

radius of nucleus

Answer 23

1 x 10^14m

Question 24

charge of subatomic molecules

Answer 24

proton= +1
neutral= 0
electron= -1

Question 25

relative mass of subatomic molecules

Answer 25

proton= 1
neutral= 1
electron= very small/0

overall charge is zero

Question 26

how to work out proton neutron and electron

Answer 26

Protons : Bottom Number

Electrons : Bottom Number

Neutrons : Top - Bottom

Question 27

what is an isotope

Answer 27

Isotopes are atoms of an element with same number or protons and electrons different numbers of neutrons

Question 28

what does it mean if an atom has a negative charge

Answer 28

atom has gained electrons

Question 28

what does it mean if an atom has a positive charge

Answer 28

atom has lost electrons

Question 28

what does group number in periodic table tell you?

Answer 28

how many electrons are in the outer shell.

Question 29

what did Dmitri Mendeleev do to the period table

Answer 29

He arranged all the elements in order of increasing
atomic weight (this was an exam question)

Grouped elements with similar properties

Left gaps for undiscovered elements

Question 30

what is the modern periodic table

Answer 30

-arranged in atomic number

-has group zero

Question 31

why is group zero inert (unreactive)

Answer 31

it has a full outer energy level so its stable.

Question 32

what is the boiling point of group zero

Answer 32

• the boiling point increases
• gthis is because as you go down the group, the atoms get bigger (more electrons)
• so there are greater intermolecular forces that we need to overcome.

Question 33

what happens to group 1 (alkali metals) metals as you go down the group

Answer 33

They get softer as you go down the group

Low melting and boiling point

All group 1 metals have 1 electron in their outer shell

This means they form 1+ ions

Question 34

what happens to reactivity as you go down group 1 ?

Answer 34

Reactivity INCREASES as we go down the group

size of atom gets bigger

The outer electron gets further away from the nucleus
There is more shielding

As the atom gets bigger there is a weaker attraction

It is more easily LOST

Question 35

what happens when group one reacts with oxygen

Answer 35

metal + oxygen –> metal oxide

Question 36

appearance of when group one reacts with oxygen

Answer 36

lithium + water

lithium floats
It fizzes steadily and becomes smaller until it eventually disappears

Sodium + water

Sodium melts to form a ball that moves around on the surface
It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears

Potassium + water

Very violent reaction
The metal melts and floats
It moves around very quickly on the surface of the water
The hydrogen ignites instantly
The metal is also set on fire, with sparks and a lilac flame

Rubidium/Caesium + water

Explodes with sparks
Violent explosions due to the rapid production of heat and hydrogen

Question 37

what is produced when alkali metal reacts with water

Answer 37

alkali + metal –> alkali metal hydroxide + hydrogen

Question 38

what happens to group 7 (halogens) as you go down the group

Answer 38

Have 7 electrons in their outer energy level/shell

Are all non-metals

Group 7 elements form molecules: 2 atoms joint by a covalent bond e.g. F2

Form 1- ion and the name ends in IDE
e.g. Fluorine - FluoRIDE

Question 39

what happens to reactivity of group 7

Answer 39

As you go down group 7

size of atom gets bigger

The outer electron gets further away from the nucleus
There is more shielding

As the atom gets bigger there is a weaker attraction

It is more difficult to GAIN an electron