Atomic Theory
Democritus 400 BC
How do we tell the Atomic mass of an atom?
Mass number = number of protons + number of neutrons
Define Half-Life
the time it takes for half of the nuclei in a sample of an isotope to decay
How do we calculate radioactive decay?
A Decay Curve
How many stars are on the flag of New Zealand?
4
Explain Daltons 4 findings for the Atom
1 All matter is composed of atoms.
2 All the atoms of a given element are alike in mass and all other respects.
3 The atoms of different elements have different masses.
4 Atoms are indestructible and preserve their identities in all chemical reactions.
Explain the difference between the atomic number and the mass number
Atomic number = number of protons
Mass number = number of protons and number of neutrons
What is the proton neutron ratio for smaller atoms?
1:1
What is the Half-life of Carbon 14?
5730 years
In Australia, which of these is NOT a colour of Smartie?
White
How did thomson use the Cathode ray to propose his model of the atom?
The British scientist J.J. Thomson (1856–1940) performed experiments in 1897 that showed the beam could be bent by an electric field. He concluded that the beam was made of tiny negatively charged particles.
Define an isotope
Isotopes are atoms of an element with the same number of protons but different numbers of neutrons.
What are the two forces in a nucleus?
Electrostatic and Strong nuclear
What atom was discovered in Uranium heavy rocks?
Helium
The sum of money paid to an insurer in return for coverage is referred to as your what?
The Premium
What particle did Rutherford propose?
Rutherford used very thin gold foil, just a few atoms thick, and fired alpha particles at the foil (Figure 4.2.5). An alpha particle is a helium nucleus, consisting of two protons and two neutrons, which gives it an overall positive charge.
What is the difference between a natural and artificial isotope?
natural isotope an isotope of an element found in nature
artificial isotope an isotope of an element produced in a nuclear reactor or particle accelerator
Define radioactive Decay
the spontaneous disintegration of certain atomic nuclei accompanied by the emission of alpha particles, beta particles or gamma radiation
Explain the differences between Alpha, beta and Gamma radiation
Alpha = 2 protons and 2 Neutrons (Helium)
Beta = 1 Electron + 1 antineutrino
Gamma = Pure energy
What year was the Premier League founded?
1992
Draw Bohr's model for the Atom.
Which is the heaviest Stable natural occurring isotope
Lead-82
Draw how the strong nuclear force impacts an nucleus
The word umpire originates from an Old French word meaning what?
Uneven