Chapter 1 - Atomic Structure

Question 1

what is the relative mass and charge on a neutron

Answer 1

mass: 1
charge: 0

Question 2

what is the relative mass and charge of a proton

Answer 2

mass: 1
charge: +1

Question 3

what is the relative mass and charge of an electron

Answer 3

mass: 1/1840
charge: -1

Question 4

define relative atomic mass

Answer 4

the average mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12.

Question 5

what must initially happen to an atom or molecule before it is put into a mass spectrometer

Answer 5

it must be ionised

Question 6

how can atoms or molecules be ionised

Answer 6

using an electron gun
or using electrospray ionisation

Question 7

describe how the electron gun ionises atoms

Answer 7

en electron is shot at an atom in a high vacuum chamber
the electron knocks off an electron off the atom to form a positive ion

Question 8

how is electrospray ionisation carried out

Answer 8

a high voltage is applied to a solution with dissolved biomolecules
the high voltage causes the solvent to become ionised and break into many small droplets which are small enough to be considered a gas

Question 9

what conditions must be present for electron impact ionisation to be successful

Answer 9

there must be a high vacuum in the chamber
the atom must be in a gaseous state

Question 10

pros of electron impact ionisation

Answer 10

it can be done on individual atoms
it is very powerful and effective

Question 11

cons of electron impact ionisation

Answer 11

it’s powerful so it may cause fragmentation in biomolecules which may cause inaccuracy in the mass spectrometer reading

Question 12

describe the method of mass spectroscopy

Answer 12

sample introduced at low pressure
electron gun or electrospray used to ionise sample
the sample becomes a positive ion
the ions are accelerated with a negatively charged plate, then focused into a beam using a magnetic field
the ions are deflected, the deflection depends on the mass to charge ratio of each ion
lightest ions are deflected the most
ions reach the detector where they gain an electron and produce a current which is detected
the size of the current is proportional to the abundance of each isotope
a mass spectrum can be produced which cab be used to calculate the Ar of the sample

Question 13

what does m/z mean

Answer 13

mass to charge ratio

Question 14

if two molecules of different mass are in one spectroscope, what about them is the same

Answer 14

the energy they are accelerated to is the same
the distance they travel is the same
the time taken to travel the distance is different
the mass is different (it is usually what you are finding)

Question 15

what equation can be used to find the velocity of a particle in a mass spectrometer given its distance and time taken to travel said distance

Answer 15

velocity = distance/time
v=d/t

Question 16

what equation can be used to find the mass of a sample when the velocity and energy are known

Answer 16

1/2mv² = KE

Question 17

how many atomic orbitals are there
name them in order of energy

Answer 17

four
s, p, d, f

Question 18

how many electrons can one orbital hold

Answer 18

2

Question 19

how many electrons can the s orbital hold in total

Answer 19

2

Question 20

how many electrons can the p orbital hold in total

Answer 20

6

Question 21

how many electrons can the d orbital hold in total

Answer 21

10

Question 22

how many electrons can the f orbital hold in total

Answer 22

14

Question 23

What orbitals does the first shell contain

Answer 23

only 1s

Question 24

What orbitals does the second shell contain

Answer 24

2s, 2p

Question 25

.

Answer 25

.

Question 26

What do blocks in the periodic table indicate

Answer 26

the last energy level of the atom

Question 27

why must the 'electrons' in boxes have different pointing arrows

Answer 27

to show th at they have different directions in their spin

Question 28

what are the three rules for filling orbitals

Answer 28

orbitals with lower energy are filled first orbitals of the same energy fill singly before they pair up only 2 elections to an orbital

Question 29

define ionisation energy (word for word)

Answer 29

the energy required go remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 30

what is the unit of IE

Answer 30

kJ/mol

Question 31

how does the IE change as electrons are removed and why

Answer 31

the energy needed becomes greater because as each electron is removed, the remaining ion becomes more positively charged as the ion becomes more positive, the electrons experience more attraction to the nucleus which required more energy to overcome

Question 32

what is the equation for the first ionisation energy of sodium

Answer 32

Na(g) ---> Na(g)^+ + -e^-

Question 33

what s the second ionisation energy for sodium

Answer 33

Na^+(g) ----> Na^2+(g) + e^-

Question 34

what factors affect ionisation energy

Answer 34

atomic radius nuclear charge electron shielding

Question 35

how does the atomic radius affect IE

Answer 35

as the radius increaces, the IE decreaces

Question 36

how does the nuclear charge affect the IE

Answer 36

the greater nuclear charge the more energy required

Question 37

how does the electron shielding affect the IE

Answer 37

the more shells, the less energy required

Question 38

define shielding in an atom

Answer 38

the number of shells in the atom

Question 39

how does IE change as you go across periods

Answer 39

there is a general increace across a single period but the IE drops dramatically at the start of a new period

Question 40

how does the IE change from group 2 to 3 and why

Answer 40

group 3 requires less energy than group 3 in group 2 the outermost electron is in an s orbital, meanwile group 3 is in a p orbital p orbitals have more energy than s orbitals so the electron needs less energy supplied to it to leave its arrangement

Question 41

how does the IE change from group 5 to 6 and why

Answer 41

group 6 requires less energy than group 5 in group 5 the p orbital is filled singly, meanwhile in group 6 an one of the of the p orbitals is fully filled the 2 electrons repel eachother in addition to the energy supplied so less energy is needed to ionise a group 6 atom than a group 5 atom

Question 42

what is hunds rule

Answer 42

within a sublevel, place one electron per orbital before pairing them

Question 43

what is the pauli exclusion principle

Answer 43

each orobital can only hold up to two electrons with opposite spins

Question 44

what is the equation to find a particles mass from its mass number

Answer 44

mass number = (mass of particle in kg / avogadros constant) × 1000

Question 45

what equation can be used to find a particles energy from its mass, time, and distance travelled

Answer 45

2KE = m(d^2/t^2)

Question 46

what equation can be used to find the mass or time of one isotope from the mass and time of another

Answer 46

m1/t1^2=m2/t2^2

Question 47

what values do two particles share when they are measured using the same mass spectrometer

Answer 47

the energy and distance travelled

Question 48

why do isotopes have the same reactivity

Answer 48

because they have the exact same electron arrangement

Question 49

write an ionic equation to represent the ionisation of molecule X in spray ionisation

Answer 49

X + H^+ -----> XH^+

Question 50

write an ionic equation to represent the ionisation of molecule X in electron bonbardment

Answer 50

X(g) + e- -----> X^+(g) + 2e^-

Question 51

when a molecule is mass spectrometered, how can you find its mr using a mass spectrum

Answer 51

average of all (m/z - 1)