C1 atomic structure and the periodic table Flashcards Preview

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Flashcards in C1 atomic structure and the periodic table Deck (82)
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1

what is the radius of an atom?

about 0.1 nanometers

2

what does the nuclear symbol of an atom tell you?

its atomic (proton) number and mass number

3

what does the atomic number tell you?

how many protons there are

4

what are isotopes?

different forms of the same element, which have the same number of protons but a different number of neutrons

5

why is relative atomic mass used instead of mass number when referring to the element as a whole?

because elements can exist as a number of different isotopes

6

what is relative atomic mass?

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

7

what is the formula to work out the relative atomic mass of an element?

relative atomic mass = sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes

8

substitute the formula for this question:
copper has two stable isotopes. Cu-63 has an abundance of 69.2% and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper.

.................................(69.2 x 63) + (30.8 x 65)
relative atomic mass = _______________
.................................................69.2 + 30.8

9

what are compounds?

substances formed from two or more elements, the atoms of each are in fixed proportions throughout the compound and they're held together by chemical bonds

10

are the nuclei of the atoms affected when a bond is made?

no

11

do metal atoms lose or gain electrons? do they form positive or negative ions?

metal atoms lose electrons to form positive ions

12

do non-metal atoms lose or gain electrons? do they form positive of negative ions?

non-metal atoms gain electrons to form negative ions

13

what is the chemical formula for ammonia?

NH3

14

what is the chemical formula for hydrochloric acid?

HCl

15

what is the chemical formula for sulfuric acid?

H2SO4

16

balance the equation H2SO4 + NaOH -> Na2SO4 + H2O

H2SO4 + 2NaOH -> Na2SO4 + 2H2O

17

name five physical methods that can be used to separate a mixture

1. filtration
2. crystallisation
3. simple distillation
4. fractional distillation
5. chromatography

18

what are the steps of paper chromatography?

1. draw a pencil line near the bottom of a sheet of filter paper
2. add a spot of ink to the line and place the sheet in a beaker of solvent, e.g. water
3. make sure the ink isn't touching the solvent
4. place a lid on top of the container to stop the solvent evaporating
5. the solvent seeps up the paper, carrying the ink with it
6. each different dye in the ink will move up the paper at a different rate, so the dyes will separate out
7. if any of the dyes in the ink are insoluble in the solvent you've used, they'll stay on the baseline
8. when the solvent has nearly reached the top of the paper, take the paper out of the beaker and leave it to dry
9. the end result is a pattern of spots called a chromatogram

19

what can filtration be used for?

filtration separates insoluble solids from liquids. It can be used if your product is an insoluble solid that needs to be separated from a liquid reaction mixture. It can also be used in purification.

20

what are two ways to separate soluble solids from solutions?

evaporation and crystallisation

21

what are the three steps of using evaporation to separate soluble solids from solutions?

1. pour the solution into an evaporating 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

22

what are the 4 steps of using crystallisation to separate soluble solids from solutions?

1. pour the solution into an evaporating dish and gently heat the solution
2. once some of the solvent has evaporated, or when you see crystals start to form (the point of crystallisation) remove the dish from the heat and leave the solution to cool
3. the salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution
4. filter the crystals out of the solution, and leave them in a warm place to dry

23

when would you use crystallisation over evaporation when separating soluble solids from solutions?

when the salt decomposes when it's heated

24

what is rock salt?

a mixture of salt and sand

25

what is simple distillation used for?

separating out a liquid from a solution

26

what are the steps of simple distillation?

1. the solution is heated. the part of the solution that has the lowest boiling point evaporates first
2. the vapour is then cooled, condenses and is collected
3. the rest of the solution is left behind in the flask

27

what is a problem with simple distillation?

you can only use it to separate things with very different boiling points

28

what process do you use to separate a mixture of liquids with similar boiling points?

fractional distillation

29

what are the steps of fractional distillation?

1. you put your mixture in a flask with a fractionating column on top and heat it
2. the different liquids will all have different boiling points, so they will evaporate at different temperatures
3. the liquid with the lowest boiling point evaporates first. When the temperature on the thermometer matches the boiling point of this liquid, it will reach the top of the column
4. liquids with higher boiling points might also start to evaporate, but the column is cooler towards the top so they will only get part of the way up before condensing and running back down towards the flask
5. when the first liquid has been collected, you raise the temperature until the next one reaches the top

30

what was the plum pudding model?

it was a model that showed the atom as a ball of positive charge with negative electrons embedded in it