Term
1. All matter is made up of tiny particles called atoms.
2. Atoms of the same element are chemically alike
3. Individual atoms of an element may not all have the same mass, but they have a definite average mass that is characteristic of that element
4. Atoms of different elements have different average masses
5. Atoms are not subdivided, created, or destroyed by ordinary chemical reactions |
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Definition
| List the ideas of the Modern Atomic Theory |
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Definition
| Most of the atomic radius is due to ___. |
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| Most of the mass of the atom is located in the _____. |
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electron
J.J. Thomson
cathode ray |
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Definition
| The first subatomic particle to be identified was the _____, by _____, through the use of the ______. |
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Rutherford
gold-foil experiment |
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Definition
| That atoms have a small, dense, positively-charged nucleus was discovered by _____ when he performed his ______. |
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Definition
True/False
The majority of an atom is empty space. |
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Definition
particles within the nucleus of an atom
(protons and neutrons) |
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positive
relatively the same as a neutron
(1.673 x 10-27 kg)
nucleus |
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Definition
| What is the charge, mass and location of a proton within an atom |
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Term
no charge
relatively the same as a proton
(1.675 x 10-27 kg)
in the nucleus |
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Definition
| What is the charge, mass, and location of a neutron in an atom |
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negative
zero mass relative to p+ and n0
in electron cloud outside of nucleus |
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Definition
| What is the charge, mass and locations of electrons in the atom? |
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Definition
| The short-range forces that hold nucleons together within the nucleus of an atom |
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Definition
| Indicates the number of protons in an atom |
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Definition
| indicates the total number of nucleons (protons and neutrons) within an atom |
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Definition
| Bacause atoms are neutral, the number of electrons is equal to the _______. |
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Definition
| Atoms of the same element with different mass numbers due to their different number of neutrons |
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Definition
| Atoms identified by the number of protons and neutrons in the nucleus |
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Definition
| the spontaneous disintegration of a nucleus into a slightly lighter and more stable nucleus, accompanied by emission of particles, EM radiation, or both |
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Definition
| particles or EM radiation emitted from the nucleus during radioactive decay |
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Definition
All nuclides beyond ____ are unstable. |
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Definition
heavy-particle radiation that is made up of 2 protons and 2 neutrons (helium nucleus)
has a 2+ charge
danger and penetrations levels are low
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Definition
electron emitted from the nucleus during nuclear decay
emitted when neutron is converted into a proton and an electron
have a 1- charge
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high-energy EM waves emitted from a nucleus as it changes from an excited state to a ground energy state
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Definition
| results in the reduction of a nucleus by 2 protons and 2 neutrons |
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Definition
| results when a neutron breaks into a proton and an electron, causing the atomic number to increase by one |
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| type of radiation that almost always follows alpha and beta emissions |
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| unstable isotopes prone to radioactive decay |
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| determines the type of radioactive decay (if any) that occurs |
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Definition
| plotted on a neutron vs proton graph that indicates the stability of nuclides |
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Definition
the time required for half the atoms of a radioactive nuclide to decay
more stability=slower decay |
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| a change in the identity of a nucleus as a result of a change in the number of its protons |
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Definition
| reactions that affect the nucleus of an atom |
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Term
E=mc2
E = energy
m = mass
c = speed of light |
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Definition
| Formula used to calculate the energy produced from mass conversions |
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Definition
| occurs when a very heavy nucleus splits into more stable nuclei of intermediate mass |
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| transmutations reactions which always results in a loss of mass |
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Definition
| a reaction in which the material that starts the reaction (such as a neutron) is also one of the products and can start another reaction |
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| the minimum amount of nuclide that provides the number of neutrons needed to sustain a chain reaction |
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Definition
occurs when light-mass nuclei combine to form a heavier, more stable nucleus
usually occurs at extremely high temperatures |
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all man-made elements
all natural elements with an atomic number greater than 83
isotopes that vary from a 1:1 ratio of neutrons to protons |
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Definition
| What elements are radioactive? |
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