atomic structure : the nucleus practice q

Question 1

symbol and mass number of atom with 3 less protons and 3 less neutrons compared to an atom of 27Al

Answer 1

21 Ne
10

Question 2

why would there be 2 peaks of one metal on an abundance and m/z graph

Answer 2

2 isotopes

Question 3

why would 2 ions have the same velocity and arrive at detector at same time

Answer 3

they have the same m/z charge

Question 4

in mass spectrometer mr of each isotope is proportional to the current generated by that isotope at the detector
explain how current is generated

Answer 4

electrons transferred at the detector
from plate to + ion

Question 5

explain how metal atom are ionised by electron impact in mass spectrometer

Answer 5

high energy electrons
fired at the atoms
from an electron gun
which knocks off 1 electron

Question 6

the 1+ ions formed are accelerated using negatively charged electric plate
why is a negatively charged plate used

Answer 6

positively charged ions are attracted to negative plate
so velocity increases

Question 7

name the order of the mass spectrometer

Answer 7

acceleration, ionisation, ion drift, detection

Question 8

describe the process of electrospray ionisation

Answer 8

sample dissolved in a volatile solvent
injected through a needle at high voltage
gains a proton/ H+

Question 9

explain how ions abundance is measured

Answer 9

ions reach the negatively charged plate
electrons flow from the plate to the positive ions
a current is produced, the size of the current is proportional to the abundance of the ion

Question 10

what is used to accelerate ions in a mass spectrometer

Answer 10

negatively charged plate

Question 11

Define relative atomic mass

Answer 11

the average mass of 1 atom of an element
on a scale in which an atom of 12C has a mass of 12

Question 12

empirical formula

Answer 12

simplest whole number ratio of atoms of each element in a compound or molecule