Atomic Structure and Isotope

Question 1

The relative mass of electrons

Answer 1

1/2000th

Question 2

Order of scientists

Answer 2

Dalton
Thompson
Rutherford
Bhor

Question 3

What did Dalton propose

Answer 3

All atoms are spheres. Each element is made of different spheres.

Question 4

What did Thompson propose

Answer 4

Discovered electron. Atom wasn’t solid. Came up with plum pudding model.

Question 5

What did Rutherford propose

Answer 5

Gold leaf experiment Discovered nucleus which was small and positively charged. Atom was mainly empty space made up of negative ‘cloud’

Question 6

What did Bhor propose

Answer 6

The cloud of electrons would collapse on itself. Proposed electrons were in fixed energy shells.
Showed proof by showing when EM radiation is absorbed they move up energy shells.

Question 7

Relative Isotopic Mass

Answer 7

Mass of an atom of an isotope compared to 1/12th of the mass of an atom of carbon-12

Question 8

Relative Atomic Mass

Answer 8

The weighted mean mass of an atom of an element compared to 1/12th of the mass of an atom of carbon-12

Question 9

What can mass spectrometry be used to do

Answer 9

provide structural information
Identify an unknown compound
Determine relative abundance of each isotope of an element

Question 10

How do mass spectrometers work

Answer 10

Sample placed into mass spectrometer
Sample vaporised then ionised to form positive ions
Ions accelerated
Heavier ions move slower and difficult to deflect so ions of each isotope are separated
Ions detected on a mass spectrum as a mass: charge ratio
Each ion adds to the signal so the greater the abundance,the larger the signal.