S1.2+S1.3

Question 1

what is a mass spectrometer used for?

Answer 1

to determine an element’s relative atomic mass from its isotope composition

Question 2

how does a mass spectrometer work?

Answer 2

by firing high energy electrons at a sample of an element to create unipositive ions, then sorted by size using electric and magnetic fields to produce a graph called a mass spectrum

Question 3

what is EM radiation?

Answer 3

a form of energy that travels as a wave

Question 4

what is the order of the EM spectrum?

Answer 4

radio, micro, IR, visible, UV, x-ray, gamma

Question 5

what is the trend from radio to gamma?

Answer 5

increase in energy, increase in frequency, decrease in wavelength

Question 6

what does the EM spectrum show?

Answer 6

shows all wavelengths of EM radiation as a continuous spectrum

Question 7

what does a line spectrum show? give an eg

Answer 7

only shows particular wavelengths eg hydrogen emission spectrum

Question 8

how does the hydrogen emission spectrum work?

Answer 8

by looking through a spectroscope aimed at a discharge tube
1) hydrogen exposed to electricity which causes promotion of electrons to a higher energy level
2) here electrons are unstable so return to a lower energy level releasing energy in the form of a photon of light
3) this light diffracts through the slit in the spectroscope separating into its individual frequencies and displaying a single line on the emission spectrum

Question 9

in hydrogen, what does a fall to level 2 give off?

Answer 9

visible light=balmer series

Question 10

in hydrogen, what does a fall to level 1 give off?

Answer 10

UV light=lyman series

Question 11

what does electrons behaving in this way provide evidence for?

Answer 11

electrons can only have a fixed value of energy

Question 12

what happens at higher energy levels to the lines?

Answer 12

the lines on the emission spectrum get closer(converge) and eventually merge to form a convergence limit which is that the energy of the electron at this point can have any value

Question 13

what is the energy it takes to reach the convergence limit called?

Answer 13

ionisation energy-the energy it takes to remove an electron from the hydrogen atom

Question 14

what are orbitals?

Answer 14

regions of space with a high probability of finding an electron

Question 15

what does the aufbau principle state?

Answer 15

electrons fill orbitals from the lowest energy level first

Question 16

what does Hund’s rule state?

Answer 16

electrons will partially fill all orbitals of a single energy level before fully filling any single orbital of a single energy level

Question 17

what does Pauli’s exclusion principle state?

Answer 17

electrons within a single orbital must have opposite spins from one another

Question 18

how many of each s, p, d, f orbitals are there?

Answer 18

s=1, p=3, d=5, f=7

Question 19

exception for Cr

Answer 19

1s2 2s2 2p6 3s6 3p6 4s1 3d5

Question 20

exception for Cu

Answer 20

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Question 21

what is ionisation energy?

Answer 21

energy required to remove 1 mole of electron from 1 mole of gaseous atoms and corresponds to the convergence limit of an emission spectrum

Question 22

E=HV

Answer 22

energy, planck’s constant, frequency

Question 23

what is nuclear charge?

Answer 23

cumulative total + charge in nucleus and directly linked to the no. of protons present

Question 24

what is electrostatic attraction?

Answer 24

attractive force of the negative electrons to the positive nucleus since opposite charges attract

Question 25

what is the shielding effect?

Answer 25

reduction of the electrostatic attraction between valence electrons and the nucleus due to the blocking by inner electrons

Question 26

how does nuclear charge change across a period and down a group?

Answer 26

increases across a period and down a group

Question 27

how does shielding change across a period and down a group?

Answer 27

increases down a group but stays the same across a period

Question 28

why does IE change down a group?

Answer 28

decreases bc nuclear charge increases, no. of electrons increases so shielding effect increases, decrease in electrostatic attraction between nucleus and valence electrons so less energy needed to remove electron

Question 29

why does IE change across a period?

Answer 29

increases, electrons are added to same shell so shielding is the same, but nuclear charge increases, electrostatic attraction between nucleus and valence electrons increases, so more energy needed to remove electron

Question 30

why does sulphur have a lower ionisation energy than phosphorus?

Answer 30

sulphur has 4 electrons in the 3p orbitals so its IE removes an electron from a p orbital containing 2 electrons, this exhibits repulsion and makes it slightly easier to remove than the 3p electron that is removed in phosphorus