Exam Q 17

Question 1

State two assumptions of Dalton’s atomic theory

Answer 1

All matter is made up of very small particles called atoms

All atoms are indivisible. They cannot be broken down into simpler particles

Question 2

Name the scientist who measured the ratio of charge to mass of the electron

Answer 2

J J Thomson

Question 3

Name the scientist who proved that the electrons in the atom reside in an electron cloud surrounding a small dense positive central nucleus

Answer 3

Rutherford

Question 4

Name the scientist who measured the charge on the electron

Answer 4

Millikan

Question 5

Outline Bohr’s atomic theory based on the hydrogen emission spectrum

Answer 5

The elctron in a hydrogen atom occupies the lowest available energy level, this is the ground state.
When the electron gains energy (e.g. electric current run through it or heat) the electron jumps from the ground state to a higher energy level.
The higher energy level is unstable and the electron falls back down to its original energy level.
As it falls, it releases a photon of light in a specific frequency, emitting light according to E2-E1=hf

Question 6

State two limitations of Bohr’s atomic theory that led to its modification

Answer 6

It did not account for elements with more than one electron.
It did not take wave-particle duality into account
Didn’t explain the discovery of sub-levels
and couldn’t account for the splitting of energy levels into sub levels

Question 7

Define atomic orbital

Answer 7

It is a region in space where there is a high probability of finding an electron

Question 8

What is the shape of a p orbital

Answer 8

A dumbell shape along the x,y,z-axis

Question 9

How many electrons can be accommodated in the p-orbital

Answer 9

2