C1-Atomic Structure

Question 1

John Dalton’s discovery

Answer 1

Atoms were first described as solid spheres

Question 2

JJ Thomson’s discovery

Answer 2

Plum pudding model- the atom is a ball of charge with electrons scattered

Question 3

Ernest Rutherford’s discovery

Answer 3

Alpha scattering experiment- mass concentrated at the centre; the nucleus is charged. Most of the mass is in the nucleus. Most atoms are empty space

Question 4

Niels Bohr’s discovery

Answer 4

Electrons are in shells orbiting the nucleus

Question 5

James Chadwick’s discovery

Answer 5

There are neutrons in the nucleus

Question 6

What determines what the element is?

Answer 6

The number of protons

Question 7

What determines the way in which an element will react?

Answer 7

The number of electrons in the outermost shell of an element’s atoms

Question 8

What were the 3 alpha particle scattering observations?

Answer 8

-Most of the particles passed straight through the gold foil
-A small number of particles were deflected by large angles as they passed through the foil
-A very small number came straight back off the foil

Question 9

What were the 3 conclusions from the alpha particle scattering experiment?

Answer 9

-Most of the atom is empty space
-There is a concentration of positive charge in the atom
-The positive charge and mass are concentrated in a tiny volume in the atom (the nucleus)