C1 - atomic structure and the periodic table

Question 1

what is an isotope

Answer 1

an atom of the same element that has the same number of protons and a different number of neutrons

Question 2

what is relative atomic mass

Answer 2

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

Question 3

what is the equation for relative atomic mass

Answer 3

RAM = sum of isotope amount x mass number
———————————————————–
sum of abundances of all isotopes

Question 4

what is a compound

Answer 4

a substance formed from two or more elements the atoms of each are in fixed proportions and are held together by chemical bonds

Question 5

what is an element

Answer 5

two or more elements or compounds mixed together not chemically bonded

Question 6

what is an atom

Answer 6

the smallest part of an element that can still be recognised as that element

Question 7

where is the nucleus located in a atom

Answer 7

the middle of the atomhs

Question 8

what does the nucleus of the atom contain

Answer 8

protons and neutrons

Question 9

what is the mass of a proton

Answer 9

1

Question 10

what is the mass of a neutron

Answer 10

1

Question 11

what is the mass of an electron

Answer 11

very small

Question 12

what is the charge of a proton

Answer 12

+1

Question 13

what is the charge of a neutron

Answer 13

0

Question 14

what is charge of an electron

Answer 14

-1

Question 15

what does the atomic number tell you

Answer 15

how many protons there are

Question 16

what does the mass number tell you

Answer 16

the total number of proton and neutrons in the atom

Question 17

what is chromatography

Answer 17

a process of separating substance in a mixture by putting dots of ink on a piece of paper and placing it into a beaker of solvent

Question 18

what are all of the dots on a piece of chromatography paper called

Answer 18

a chromatogram

Question 19

what are 2 methods to separate soluble solids from soloutions

Answer 19

evaporation
crystallisation

Question 20

evaporation method

Answer 20

pour the soloution into an evaporating dish
slowly heat the soloution. the solvent will evaporate and the soloution will get more concentrated eventually crystals will form. keep heating the evaporating dish untill all you have left are dry crystals

Question 21

crystalisation method

Answer 21

pour the soloution into an evaporating dish and gently heat the soloution. some of the solvent will evaporate and the soloution will get more concentrated
once some of the solvent has evaporated remove the dish from the heat and leave the solvent to cool
the salt should start to form crystals as it becomes insoluble in the cold highly concentrated soloution
filter the crystals out of the soloution and leave them in a warm place to dry. you could also use a drying oven or a desiccator

Question 22

simple distillation method

Answer 22

the soloution is heated. the part of the soloution that has the lowest boiling point evaporates first
the vapour is then cooled condences and is collected
the rest of the soloution is left behind in the flask

Question 23

what is a problem with simple distillation

Answer 23

you can only use it to spearte things with a similar boiling points - if the temperature goes higher than the boiling point of the substance with the higher boiling point they will mix again

Question 24

fractional distillation method

Answer 24

put your mixture in a flask and put a fractionating column on top then you heat it
the different liquids will all have different boiling points
the liquid with the lowest boiling point evaporates first. when the temperature on the thermometer matches the boiling point of this liquid will reach the top of the column
liquids with higher boiling point mihgt 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
when the liquid has been collected you raise the temperature until the next one reaches the top

Question 25

describe how the plum pudding model of the atom came about

Answer 25

at the start of the 19th century John Dalton described atoms as solid spheres and said the different spheres make up the different elements
then in 1897 J-J Thompson concluded from his experiments that atoms were not solid spheres. His measurements of charge and mass showed that an atom must contain even smaller,negatively charged particles - electrons
this new theory was known as the plum pudding model. it shows an atom as a ball of positive charge with electrons stuck in it

Question 26

who proved that the plum pudding model of the atom was wrong

Answer 26

ernest rutherford

Question 27

describe how the nuclear model of the atom came about

Answer 27

in 1909 ernest rutherford and his student conducted the famous alpha particles scattering experiment. They fired positively charged alpha particles at an extremely thin sheet of gold
this meant that the plum pudding model couldn’t be right so rutherford came up with the nuclear model of the atom

Question 28

what is the nuclear model of the atom

Answer 28

a tiny positively charged nucleus where most of the mass is concentrated a cloud of negative electrons surround the nucleus,so most of the atom is empty space

Question 29

who discovered the neutron

Answer 29

james chadwick

Question 30

how did mendelev arrange the periodic table

Answer 30

he put the elements in order of atomic weight
he left gaps to make sure that elements with similar properties stayed in the same groups. some of the gaps indicated the existence of undiscovered elements and allowed mendeleev to predict what their properties might be. most of the predicted elements ended up being correct