CC3B Atomic number and mass number Flashcards
1
Q
What did Ernest Rutherford discover from his gold foil experiment
A
He shot a beam of positively charged particles at sheet of gold foil
Most particles passed straight through suggesting that atoms were mostly empty space
A few particles were deflected and a few bounced directly back showing that there must be a tiny dense and positively charged nucleus
2
Q
Describe Rutherfords new model of the atom
A
Mass is concentrated in the central nucleus
Mostly empty space
Electrons travel in random paths around the nucleus
3
Q
What does the atomic number of an atom represent
A
The number of protons (the bottom one)
4
Q
What does the mass number of an atom mean
A
The mass number is the number of protons and neutrons (the top one)
