C2-1 History of the atom

Four chemists who added to our understanding of the structure of the atom, in order of their discoveries, were...

• ...Thompson, Dalton, Rutherford & Bohr

• ...Rutherford, Thompson, Dalton & Bohr

• ...Dalton, Thompson, Rutherford & Bohr

• ...Dalton, Rutherford, Thompson & Bohr

At the start of the 19th Century John Dalton described atoms as solid spheres made up of the different chemical elements we know today. What name was give to Dalton's model atom?

• Plum Pudding

• Billiard Ball

• Electron in shell

• Nuclear model

in 1904 J.J. Thompson concluded from his experiments that atoms were not solid spheres. What sub atomic particle did he discover that made him say this?

• Neutron

• Proton

• Electron

• Nucleon

In 1911 Rutherford fired alpha particles at a thin sheet of gold atoms. Based on the plum pudding model Rutherford expected some particles to be slightly deflected based on the positive charge spread throughout the model. The results he found were:-

• Most alpha particles passed straight through.

• A few alpha particles were slightly deflected and a few passed straight through.

• A few alpha particles were completely deflected, a few were partially deflected but most passed straight through

• Most alpha particles were completely deflected and a few were partially deflected.

Based on Rutherford's experiments he had to come up with a new model of that atom that fit with the new evidence. Rutherford's model was know as...

• Plum pudding

• Electron in shell

• Nuclear model

• Billiard ball

Scientists realised that electrons in a cloud around at he nucleus, (Rutherford's model) would be attracted to the nucleus and the atom would collapse. Which scientists suggested that the electrons were contained in shells around the nucleus?

• Dalton

• Rutherford

• Bohr

• Thompson

Bohr's theory of atomic structured was supported by many experiments and helped explain many other scientists observations at the time.

Which of these statements was NOT part of Bohr's theory?

• Each atom has a fixed number of shells

• Electrons were contained in shells

• Electrons orbit the nucleus in fixed shells

• Each shell is a fixed distance from the nucleus

Which model belongs to which scientist?

• Billiard ball

  Plum pudding

  Nuclear

  Electron in shell

• Plum pudding

  Billiard ball

  Electron in shell

  Nuclear

• Nuclear

  Billiard ball

  Plum pudding

  Electron in shell

• Electron in shell

  Plum pudding

  Billiard Ball

  Nuclear

What did J. J. Thompson discover?

• The plum pudding model

• The electron

• Positive nucleus

• Shells around the nucleus

Scientists have continued to develop ideas of the model atom based on the evidence available. Whose model did not contain any fundamental particles?

• A

• B

• C

• D