C1 : Alpha - Scattering experiment

Question 1

What were the beliefs of the Ancient Greeks

Answer 1

That everything is made up of atoms and that atoms are tiny spheres that cannot be divided

Question 2

When were electrons discovered

Answer 2

In 1897, scientists discovered that atoms contain tiny negative particles. This showed that atoms are not spheres that cannot be divided. Atoms have an internal structure

Question 3

What did the plum pudding model show

Answer 3

The plum pudding model demonstrated that atoms were a ball of positive charge with negative electrons embedded inside it

Question 4

How did scientists disprove the plum pudding model

Answer 4

By carrying out the Alpha - Scattering experiment

Question 5

How did the Alpha - Scattering experiment work

Answer 5

. Scientists took a piece of gold foil (a few atoms thick)
. Scientists fired alpha particles at the gold (alpha particles have a positive charge)
. Most of the alpha particles went straight through the gold foil telling scientists that atoms are mostly empty space
. Some of the particles were deflected meaning the center of the atom must have a positive charge
. Some of the particles bounced straight back meaning the center of the atom must have a great deal of mass

Question 6

What model of the atom replaced the plum pudding model

Answer 6

Nuclear model

Question 7

Nuclear model

Answer 7

. Most of the atom is empty space
. Small positive nucleus in the center
. Negative electrons that orbit the nucleus

Question 8

When was the Plum pudding model discovered

Answer 8

1897 by J J Thompson