History of the Atomic Model

At first, people thought that all atoms were simply...

• Clouds

• Hollow balls

• Solid spheres

• Like bricks

The greek word "atomus" originally meant..

• Tiny

• Round

• Identical

• Indivisible (can't be split up)

A material which is made up of atoms which are all the same is called an ....

James Dalton was a scientist in the 1800s. He said that atoms of different elements could join together to form...

• compounds

• mixtures

• chemicals

• co-ordinates

In 1904 JJ Thompson discovered that atoms actually contained particles called electrons. Which of these best describes an electron?

• Much much smaller than atom, positively-charged

• Much much smaller than atom, negatively-charged

• Make up most of the mass of the atom, negatively-charged

• Contain most of the mass of the atom, no charge

Which of these is the best description of Thompson's model?

• A solid ball of positive charge with electrons randomly stuck in it

• A cloud of positive charge with electrons randomly dotted through it

• A cloud of positive charge with electrons in regular orbits inside it

• A positive nucleus with electrons dotted randomly around it

In Rutherford and Marston's famous experiment, what did they fire through a very thin piece of gold foil?

• A laser

• A stream of electrons

• A stream of positively-charged particles

• A stream of neutrons

Their ideas were based on Thompson's Plum-Pudding model. So at first they thought all the tiny positive particles would...

• Go straight through the gold atoms

• Bounce straight back off the gold atoms

• Be deflected in random directions

• Stop dead

What actually happened to the tiny positive particles?

• They all bounced straight back off the gold

• A few bounced back, some were deflected, most west straight through

• Most bounced back or deflected, just a few went straight through

• All went straight through as expected

Rutherford concluded that atoms must not be a cloud of positive charge, but must instead contain a nucleus. The nucleus is...

• Tiny, light and negatively-charged

• Tiny, light and positively-charged

• Relatively large and positively-charged

• Tiny, dense and positively-charged