Chemistry Test 3: Nuclear Chemistry – Flashcards
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Nucleons
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Particles in the nucleus (protons and neutrons)
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Nuclear Chemistry
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Study of reactions that are caused by a change in the nucleus of an atom
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Radioactive atom
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Nucleus decays spontaneously and emits radiation (energy and/or particles) to form a more stable substance/element.
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Radioisotope
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An isotope of an element that is radioactive Note: all isotopes of elements with atomic # >83 are both man made and radioactive
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Stability of Nuclei
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1. Elements with an atomic # that is greater than 83 have no stable isotopes 2. Rounded mass # on periodic table is the most common, stable isotope.
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Transmutation
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Disintegration of the nucleus. Radiation changes one element to another. 2 types of transmutation: natural and artificial.
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Alpha particles
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-A package of high energy electrons that consists of 2 protons and to neutrons. -Identical to He nucleus. -After an alpha particle is emitted from an element, it turns into new element. -Low penetration ability, can be stopped by a piece of paper
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Beta particles
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-High speed electrons. -Proton gives of an beta particle (electron) and becomes a neutron. -Proton is removed -Moderate penetration ability, can be stopped by glass, aluminum, heavy clothing
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Positron particles
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-Particle similar to an electron, but has a positive charge. -Neutron gives off a positron and turns into a proton -Proton is added.
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Gamma rays
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-High energy electromagnetic waves (similar to x-rays) -Does not consist of particles -Does not consist of particles - no charge and no mass
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Decay series
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A series of radioactive nuclides produced by successive radioactive decay
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Half-life
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The time it takes for half of the existing radioactive atoms to decay and form atoms of a new element
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Nuclear fission
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A neutron hits the nucleus of an atom, causing it to break into 2 or more lighter and smaller parts. Occurs in nuclear power plants.
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Nuclear fusion
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Two particles combine to create a larger, denser nucleus. Occurs in stars.
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Artificial Transmutation
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A change in the nucleus caused by bombarding it with a high energy particle
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High energy particles:
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1. Proton 2. Neutron 3. Alpha particle 4. Deutium or tritium
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Valence electrons
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Electrons in the outer shell of an atom
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Excited State
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Some electrons are in higher levels
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Ground state
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Electrons are in the lowest possible energy levels
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Bright Line Spectrum
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Comes from emission of light from excited states of the atom. Each atom has electron "levels". When an atom moves from an excited state to ground state, electrons in the upper level drop into the lower level and specific frequencies of light are emitted. The line positions are characteristic of different atoms (elements).
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Nuclear Chain Reaction
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A process in which neutrons released in fission produce an additional fission in at least one further nucleus.
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Spectroscope
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Any of various instruments used to analyze the component parts of a sample by separating its parts into a spectrum
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Tracer
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a chemical compound in which one or more atoms have been replaced by a radioisotope so by virtue of its radioactive decay it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows
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Continuous spectrum
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A continuous spectrum contains many different colors with no gaps. Perfectly white light shined through a prism causes dispersion of the light, and we see a rainbow.
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Radioactive dating
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A technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they formed.
