Unit 1: Atomic Structure and the Periodic Table

Question 1

What is Hund’s rule?

Answer 1

if there is more than one orbital in a sub-shell, electrons are initially added to orbitals so that the electrons have parallel spins before pairing up

Question 2

What is Pauli’s exclusion principal?

Answer 2

electrons in the same orbital have opposite spins (maximum separation, minimum repulsion)

Question 3

What is the order of orbitals?

Answer 3

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

Question 4

Define an isotope

Answer 4

atoms with the same atomic number but with different number of neutrons

Question 5

define relative isotopic mass

Answer 5

mass of an atom relative to 1/12th mass of an atom of carbon-12

Question 6

why do isotopes of the same element behave identically in chemical reactions?

Answer 6

they have the same electron configuration

Question 7

Why might a sample not have the same Mr?

Answer 7

it may not be from Earth

Question 8

What is the first step in a mass spectrometer?

Answer 8

Ionisation: an electron is knocked out when fast/high energy electrons strike the gaseous sample

Question 9

What is the second step in a mass spectrometer?

Answer 9

Acceleration: positive ions accelerated by an electric field/charged plates

Question 10

What is the third step in a mass spectrometer?

Answer 10

Deflection: the positive ions are deflected by a magnetic field produced by an electromagnet

Question 11

Equation for the ionisation of a sample in a mass spectrometer

Answer 11

X(g) + e- = X+(g) + 2e-

Question 12

What is one use of a mass spectrometer?

Answer 12

testing for narcotics

Question 13

What will undergo the greatest deflection?

Answer 13

The ion with the highest charge density

Question 14

Define relative atomic mass

Answer 14

the mean mass of an atom relative to 1/12th mass of an atom of carbon-12

Question 15

How do you calculate RAM?

Answer 15

(total mass x abundance)/(total abundance)

Question 16

What energy block is an element in?

Answer 16

the sub-shell containing the highest energy electron

Question 17

Why does atomic radius increase across the period?

Answer 17

nuclear charge increases, electron shielding remains the same, greater nuclear attraction from the shells of electrons

Question 18

Why does the atomic radius increase down the group?

Answer 18

more shells of electrons, electron shielding outweighs increase in nuclear charge, less nuclear attraction

Question 19

Define the 1st IE

Answer 19

the heat energy required to remove one electron from each atom of one mole of gaseous atoms

Question 20

equation for the 1st IE

Answer 20

X(g) = X+(g) + e-

Question 21

Equation for the second IE

Answer 21

X+(g) = X2+(g) + e-

Question 22

What is the magnitude of IE affected by?

Answer 22

distance of outermost electron from nucleus, atomic radius

Question 23

what is the trend in IE across the period?

Answer 23

it increases

Question 24

Why is group 2’s 1st IE greater than group 3’s?

Answer 24

group 3, p1 electron has higher energy level than the s-orbital electron and so experiences greater shielding

Question 25

Why are group 5's IEs greater than group 6's?

Answer 25

group 5 atom, charge of 3p electrons is evenly distributed (more stable) whilst in the group 6 atom there are 4 electrons in the p-sub-shell paired electrons in the same shared p-orbital experience repulsion

Question 26

When are ions isoelectronic?

Answer 26

if their electronic configuring (as ions) is the same

Question 27

Why do elements in the same group have similar but not identical properties?

Answer 27

same number of outer shell electrons, but the ease at which they're lost or gained is different

Question 28

What is the aufbau principle?

Answer 28

electrons fill the lowest energy orbital first before filling the next lowest