(a) State two assumptions of Dalton's atomic theory of 1808. (b) The electron was the first of the sub-atomic particles to be discovered. It was identified in experiments using cathode rays that were carried out in the late nineteenth century. Name the scientist (i) who, about 1897, measured the ratio of charge to mass of the electron, e/m, (ii) who, about 1910, proved that the electrons in an atom reside in an electron cloud surrounding a small dense positive central nucleus. (iii) who, about 1911, measured the charge on the electron, e. (c) The arrangement of the electrons in the electron cloud proposed in 1913 by Bohr, pictured on the right, was consistent with the hydrogen emission spectrum. Outline Bohr's atomic theory based on the hydrogen emission spectrum. (d) State two limitations of Bohr's theory that led to its modification. (e) Define atomic orbital. Draw the shape of the p-orbital. State the maximum number of electrons that can be accommodated in a p-orbital.

Leaving Cert Chemistry Electron Arrangement: (a) State two assumptions of Da

(a) State two assumptions of Dalton's atomic theory of 1808 - Leaving Cert Chemistry - Question 5 - 2010

Question 5

(a) State two assumptions of Dalton's atomic theory of 1808. (b) The electron was the first of the sub-atomic particles to be discovered. It was identified in expe... show full transcript

Worked Solution & Example Answer:(a) State two assumptions of Dalton's atomic theory of 1808 - Leaving Cert Chemistry - Question 5 - 2010

Step 1

State two assumptions of Dalton's atomic theory of 1808.

96%

114 rated

Answer

Atoms are small and indivisible particles.
All atoms of a given element are identical in mass and properties.

Step 2

Name the scientist who, about 1897, measured the ratio of charge to mass of the electron, e/m.

99%

104 rated

Answer

The scientist is J.J. Thomson.

Step 3

Name the scientist who, about 1910, proved that the electrons in an atom reside in an electron cloud surrounding a small dense positive central nucleus.

96%

101 rated

Answer

The scientist is Ernest Rutherford.

Step 4

Name the scientist who, about 1911, measured the charge on the electron, e.

98%

120 rated

Answer

The scientist is Robert Millikan.

Step 5

Outline Bohr's atomic theory based on the hydrogen emission spectrum.

97%

117 rated

Answer

Bohr's atomic theory states that:

Electrons occupy fixed energy levels (orbits) around the nucleus.
An electron in a lower energy level can be excited to a higher energy level by absorbing a specific amount of energy (photon).
The electron will emit a photon and fall back to a lower energy level when it returns to its ground state.
The energy of the emitted/absorbed photon corresponds to the difference in energy between the two energy levels.

Step 6

State two limitations of Bohr's theory that led to its modification.

97%

121 rated

Answer

Bohr’s model only worked for hydrogen and could not accurately predict the spectra of other elements.
It did not take wave-particle duality into account, limiting its applicability to multi-electron systems.

Step 7

Define atomic orbital.

96%

114 rated

Answer

An atomic orbital is a region (space) around the nucleus of an atom where there is a 99% probability of finding an electron, indicating where the electron is most likely to be found.

Step 8

Draw the shape of the p-orbital.

99%

104 rated

Answer

The p-orbital has a dumbbell shape:

  |        |
  |        |
---+---   ---+---
  |        |
  |        |

Step 9

State the maximum number of electrons that can be accommodated in a p-orbital.

96%

101 rated

Answer

The maximum number of electrons that can be accommodated in a p-orbital is 6.

(a) State two assumptions of Dalton's atomic theory of 1808 - Leaving Cert Chemistry - Question 5 - 2010

Worked Solution & Example Answer:(a) State two assumptions of Dalton's atomic theory of 1808 - Leaving Cert Chemistry - Question 5 - 2010

State two assumptions of Dalton's atomic theory of 1808.

Name the scientist who, about 1897, measured the ratio of charge to mass of the electron, e/m.

Name the scientist who, about 1910, proved that the electrons in an atom reside in an electron cloud surrounding a small dense positive central nucleus.

Name the scientist who, about 1911, measured the charge on the electron, e.

Outline Bohr's atomic theory based on the hydrogen emission spectrum.

State two limitations of Bohr's theory that led to its modification.

Define atomic orbital.

Draw the shape of the p-orbital.

State the maximum number of electrons that can be accommodated in a p-orbital.

Join the Leaving Cert students using SimpleStudy...