1.1 Atomic Structure Paper 1 and 2

Question 1

Which is the letter used to represent the atomic number of an atom

Answer 1

Z

Question 2

What does the atomic number tell us about an element

Answer 2

Number of protons in an atom

Question 3

What letter represents mass number

Answer 3

A

Question 4

How is the mass number calculated

Answer 4

Mass number = number of protons + number of neutrons

Question 5

Define relative atomic mass

Answer 5

Average mass of all isotopes of an element compared to 1/12 the mass of an atom of carbon 12

Question 6

What are isotopes of an element

Answer 6

Different forms of the same element containing the same number of protons but different numbers of neutrons
They have the same chemical properties

Question 7

How many orbitals and electrons does an s shell contain

Answer 7

1 orbital
2 electrons

Question 8

How many orbitals and electrons does a p shell contain

Answer 8

3 orbitals
6 electrons

Question 9

How many orbitals and electrons does a d shell contain

Answer 9

5 orbitals
10 electrons

Question 10

Does 3d or 4s have a higher energy

Answer 10

3d

Question 11

What is an orbital

Answer 11

A region around the nucleus that can hold up to 2 electrons

Question 12

What would be the relationship between 2 electrons in the same orbital in terms of their spin

Answer 12

Have opposite spin as repel eachother as both negative

Question 13

Why does chromium not fit the trend for electronic configuration

Answer 13

It only has 1 electron in its 4s orbital before filling 3d
1s2… 3p6 4s1 3d5

Question 14

Why does copper not fit the trend for electronic configuration

Answer 14

It only has 1 electron in its 4s orbital before filling 3d
1s2…. 3p6 4s1 3d10

Question 15

Which sub shell do ions lose electrons from first

Answer 15

4s

Question 16

What does electron impact do

Answer 16

An electron gun (hot wire filament with current through it emitting electrons) knocks off one electron from each particle to form 1+ molecular ions

Question 17

What does electrospray do

Answer 17

Sample dissolved in volatile solvent and injected through a fine hypodermic needle attached to positive terminal of a high voltage power supply into mass spec as a fine mist

Question 18

When would you use the different types of ionisation in mass spec

Answer 18

Electron impact - organic or inorganic molecules with a low formula mass
Electrospray - substances with higher molecular mass including biological molecules eg proteins

Question 19

Describe how TOF acceleration works

Answer 19

Positive ions attracted towards a negatively charged plate(electric field), same KE

Question 20

Describe how TOF ion drift works

Answer 20

Ions pass through hole in plate, form a beam with constant kinetic energy, travel along tube to detector.

Question 21

Describe how TOF detection works

Answer 21

Positive ions hit negative plate, current produced, m/z value and time of flight recorded. Largest current from most abundant ions

Question 22

Define first ionisation energy

Answer 22

The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions