Physical- Atomic Structure

Question 1

What letter is the symbol for atomic number in the periodic table?

Answer 1

Z

Question 2

What letter is the symbol for mass number in the periodic table?

Answer 2

A

Question 3

What is the relative atomic mass?

Answer 3

The average mass of all isotopes of an element compared to 1/12 the mass of an atom of Carbon 12

Question 4

What is a isotope of an element?

Answer 4

Different forms of the same element, both containing the same number of protons but a different number of neutrons

Question 5

How do you work out the average mass of an element?

Answer 5

(abundance of A x mass of A) + (abundance of B x mass of B) divided by the total abundance

Question 6

What is Avogadro’s constant?

Answer 6

6.02 x 10-23

Question 7

How do you work out the mass of one atom?

Answer 7

Mass of one mole divided by Avogadro’s constant (convert to kg)

Question 8

What is a mass spectrometer?

Answer 8

An instrument used to accurately determine the relative atomic mass

Question 9

What are the six stages of a mass spectrometer?

Answer 9

1- vaporisation
2- ionisation
3- electric field
4- ion drift
5- detector
6- mass spectrum

Question 10

What are the two types of ionisation for a mass spectrometer?

Answer 10

Electron impact- electron gun fired at atom, knocks of outer shell electron to form a +1 ION
Electrospray ionisation- sample is dissolved in a volatile solvent and injected through a needle which is attached to a high voltage power supply

Question 11

What are the two equations used in TOF calculations?

Answer 11

KE=1/2 x m x v2
v=d divided by t

Question 12

What is the first ionisation energy?

Answer 12

The minimum amount of energy needed for one mole of the outermost electrons to be removed from one mole of atoms in a gaseous state

Question 13

What is the equation for the first ionisation energy in an element?

Answer 13

Mg(g) —> Mg+(g) + e-

Question 14

How are ions detected in a mass spectrometer?

Answer 14

When they hit the detector they generate a current

Question 15

How is the abundance of isotopes measured in a mass spectrometer?

Answer 15

The current produced is proportional to the abundance

Question 16

Why do isotopes have similar chemical properties?

Answer 16

Because they have the same number of electrons in their outer shell

Question 17

How do successive ionisation energies give evidence for sub-shells and shells?

Answer 17

A bigger jump in the amount of energy required between successive ionisation energies indicates a change in sub-shells or shells since the electrons are closer to the nucleus

Question 18

What is the second ionisation energy?

Answer 18

The energy required to remove one mole of electrons from one mole of gaseous positive ions to form one mole of 2+ gaseous ions and one mole of electrons