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Unit 4-Atoms
Covers topics from History of Atom to Nuclear Reactions and Equations
| Question | Answer |
|---|---|
| In 460 B.C., who developed the idea of the atom? | Democritus |
| What did John Dalton do in 1766-1844? | Created the atomic theory and stated that the atom is one, solid sphere. |
| What did J.J. Thomson's Cathode Ray Experiment show? | Electrons are embedded in a ball of positive charge. They are not indivisible, but are composed of smaller particles called subatomic particles. |
| Who used the Gold Foil Experiment to reveal the true atom arrangement-atom is nearly all empty space? | Ernest Rutherford |
| What are isotopes? | Atoms of the same element that differ in mass due to difference in number of neutrons. |
| What does the mass number (A) do? | Defines a particular isotope Determines total number of protons and neutrons |
| What is an ion? | An atom with a charge |
| How are ion's formed? | By changing the number of electrons. It is still the same element, only charged. |
| What is Cation? | Losing an electron. Positive ion. |
| What is Anion? | Gaining an electron. Negative ion. |
| What is the Average Atomic Mass? | The weighted average mass of an element's isotope. Depends on percent abundance of each isotope. |
| How do you calculate Average Atomic Mass? | 1. Convert all percents to decimal form 2. Multiply each mass by its percent abundance 3. Add together for average atomic mass |
| How do you find relative abundances? | Work backwards to determine the relative abundance of isotopes. |
| What is radiation? | Spontaneous emission of particles from the nuclei of unstable radioisotopes |
| Marie Curie coined what term? | Radioactive |
| When are radioisotopes more stable? | When they have high nuclear binding energy, when they have even numbers of protons and neutrons, and when they are along the Ideal N/Z ratio (neutron/proton)band. |
| What is radioactive nuclear decay? | Unstable radioisotopes the spontaneously break down. These emit particles (radiation) and form more stable isotopes. |
| What is transmutation? | When the number of proton's in the nucleus must change. |
| What is Alpha Decay? | Release of alpha particles. 4He 2 |
| What is Beta Minus Decay? | High energy electrons where the neutrons are changed to protons. 0e -1 |
| What is Positron Emission? | Emission of positron (anti electron) where the protons are converted to neutrons. 0e +1 |
| What is Electron Capture? | When the nucleus captures an electron. 0e -1 |
| What is Gamma Emission? | Occurs with "nuclear rearrangement" (high to low energy state). Pure energy that can occur with other types of decay. 0Y 0 |
| What is mass defect? | The mass lost when forming/rearranging nuclei |
| What is nuclear binding energy? | The energy produced when forming/rearranging nuclei. |
| What is E=mc^2 | A mass energy equivalence equation used to find energy emitted when forming/rearranging nuclei. |
| What is Fusion? | When the lighter nuclei join together. |
| What is Fission? | When the heavier nuclei split and break apart. Enormous energy release causes chain reaction. Neutrons released in the fission of one atom trigger fission in another nearby atom. |
| What is Half-Life? | The time it takes for half of a sample of radioactive isotopes to decay. |
| Half-Life Equation | N=No(1/2)^t/t1/2 |
Created by:
HopeSpangler
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