2.1.1 Atomic Structure and Isotopes

Question 1

electron relative mass

Answer 1

1/2000

Question 2

O2
8 protons 8+charge
8 neutrons 0 charge
10 electrons 10- charge
total charge:

Answer 2

2-

Question 3

relative isotopic mass

Answer 3

The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12.

Question 4

relative atomic mass

Answer 4

The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12

Question 5

relative molecular mass

Answer 5

The mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12

Question 6

outline how mass spectrometry is carried out:

1 placed

2 v then i to form p i

3 i a, heavier, lighter, so i of each i s

4 i are d on ms as a m-t-c … each i reaching d adds to… so the,,,,,the,,,,,

equation:

• for an ion with one +ve charge, this ratio is….. to the ……….. whic is recoreded on the ..-….. of the spectrum

Answer 6

1 a sample is placed in the mass spectrometer

2 the sample is vapourised and then ionised to form
positive ions

3 the ions are accelerated. heavier ions move more slowly and are more difficult to deflect than lighter ions, so ions of each isotope are separated

4 the ions are detected on a mass spectrum as a mass-to-charge ratio m/z.
each ion reaching the detector adds to the signal so the greater the abundance, the larger the signal
relative mass of ion
equation: mass-to-change ratio m/z= —————————–
relative chrge of ion

• equivalent, relative isotopic mass, x-axis

Question 7

1+ polyatomic ion (1)

Answer 7

ammonium NH4 +

Question 8

1- polyatomic ionS (5)

Answer 8

~ hydroxide OH- 
~ nitrate NO3 - 
~ nitrite NO2 - 
~ hydrocarbonate HCO3 - , 
~ manganate(VI) {permanganate} MnO4 -

Question 9

2- polyatomic ionS (4)

Answer 9

~ carbonate CO3 2-
~ sulfate SO4 2-
~ sulfite S03 2-
~ dichromate (VI) Cr2O7 2-

Question 10

3- polyatomic ion (1)

Answer 10

phosphate PO4 3-