Define physical change
a change in the state or properties of matter without any accompanying change in chemical composition
| Term | Definition |
|---|---|
Define physical change | a change in the state or properties of matter without any accompanying change in chemical composition |
A chemical changes produces how many types of matter? | 1 or more |
Is the matter that a chemical change produces different from the matter present before the change? | Yes |
A chemical change involves changes in the ____ of the matter present | electronic structure (electrons) |
Does a chemical change involve changes to the atoms themselves? | No |
A nuclear change involves changes to the _____ in matter | nuclei |
A chemical change changes the way elements are ______ | combined |
A nuclear change changes an atom's ____ | nucleus |
(Chemical change) Different isotopes of an element have similar ____ | chemical properties |
Energy changes in chemical reactions are generally (small/large) in magnitude | small |
(Chemical change) Only electrons in the ____ level of the atom are involved | outer level |
In a chemical change, are new elements formed? | No |
(Nuclear change) Different isotopes of an element have different ____ | nuclear properties |
Energy changes in nuclear reactions can be many orders of magnitude (smaller/larger) than chemical reactions | larger |
Is the nucleus of an atom involved during nuclear change? | Yes |
May elements be changed into new elements during nuclear change? | Yes |
Define nuclear chemistry | the study of reactions that involve changes in nuclear structure |
When referring to a single type of nucleus, the term _____ is often used. It is identified by what symbol? | nuclide; identified by an X with an A in the top left corner and an Z is the bottom left corner |
Define nucleons | protons and neutrons, when referred to collectively |
A strong nuclear force is the force of attraction that holds the ____ together | nucleus |
Name the four fundamental forces known to exist | electromagnetic force, gravitational force, the strong nuclear force, and the nuclear weak force |
Define mass defect | the loss in mass that occurs when protons and neutrons combine to form a nucleus |
Define binding energy | the amount of energy holding a nucleus together |
The larger the binding energy, the more (stable/unstable) the nucleus | lstable |
Give the formula for calculating binding energy. State what the letters mean. | ΔE = Δmc² ; E is binding energy, m is the mass defect, c is the constant (speed of light) |
Give the formula for calculating the mass of an atom | (# of protons x 1.0073 amu) + (# of neutrons x 1.0087 amu) + (# of electrons x 0.00055 amu) |
A stable nucleus is one that (can/cannot) be transformed into another configuration without adding energy from the outside | cannot |
Define the band of stability | the small band of stable isotopes on a plot of the number of neutrons vs the number of protons |
Nuclei to the left or right of the band of stability are (stable/unstable) and exhibit _____ | unstable; radioactivity |
What happens to the nuclei that are to the left or to the right of the band of stability? What are these nuclei called? | they spontaneously decay into other nuclei that are either in, or closer to, the band of stability; radioisotope |
Generally, the number of _____ is equal to or greater than the number of _____ in a stable nuclide | neutrons; protons |
The number of neutrons to protons is nearly equal for elements of (high/low) atomic number | low |
Explain why elements above atomic number 20 tend to have a higher ratio of neutrons to protons in a stable nuclide | The larger nuclei have more proton-proton repulsions, so they require a larger number of neutrons to provide compensating strong forces to overcome electrostatic repulsions and hold the nucleus together |
Nuclides with (even/odd) numbers of protons, neutrons, or both tend to be stable | even |
List the "magic numbers" ; What do they mean | 2, 8, 20, 28, 50, 82, 126; if an element has a "magic number" for its number of protons, neutrons, or both, then it's probably stable |
Describe alpha particles | High-energy helium nuclei consisting of two protons and two neutrons |
Describe beta particles | high-energy electrons |
Describe positrons | particles with the same mass as an electron but with 1 unit of positive charge |
Describe protons | nuclei of hydrogen atoms |
Describe neutrons | Particles with a mass approximately equal to that of a proton but with no charge |
Describe a gamma ray | Very high-energy electromagnetic radiation |
A balanced chemical reaction equation reflects the fact that during a chemical reaction, bonds ____, and atoms ____, but the total numbers of ____ of each element are ____ | break and form; rearrange; atoms; conserved and do not change |
A balanced nuclear reaction equation indicates that there is a rearrangement during a nuclear reaction, but of ____, rather than ____ | nucleons; atoms |
(Conversation laws of nuclear reactions) The sum of the mass numbers of the reactants equals the _____ | sum of the mass numbers of the products |
(Conversation laws of nuclear reactions) The sum of the charges (the atomic number - number of protons) of the reactants equals _____ | the sum of the charges of the products |
During a nucelar reaction, how to you calculate the sum of the charges? | the atomic number - number of protons |
Define radioactive decay | the spontaneous change of an unstable nuclide into another |
Define alpha (α) decay | the emission of an alpha particle from the nucleus |
Define beta (β) decay | the emission of an electron from a nucleus |
Gamma (γ) emission is observed when what happens? | when a nuclide is formed in an excited state and then decays into its ground (stable) state with the emission of a γ ray |
Define positron emission (β^+ decay) | the emission of a positron from the nucleus |
Define electron capture | process in which the nucleus captures one of the inner electrons in an atom |
Give the change in mass/atomic numbers for alpha decay | A: decrease by 4; Z: decrease by 2 |
Give the change in mass/atomic numbers for beta decay | A: unchanged; Z: increase by 1 |
Give the change in mass/atomic numbers for gamma decay | A: unchanged; Z: unchanged |
Give the change in mass/atomic numbers for positron emission | A: unchanged; Z: decrease by 1 |
Give the change in mass/atomic numbers for electron capture | A: unchanged; Z: decrease by 1 |
Which process decreases the neutron/proton ratio? (also type its representation) | Beta decay (Neutron ---> Proton + β^-) |
Which 3 processes increase the neutron/proton ratio? (also type their representation) | proton emission (Proton ---> Neutron + β^+), electron capture (Proton + Electron ---> Neutron), and alpha decay |
Define nuclear transmutation | the conversion of one nuclide into another |
Give 2 examples of nuclear transmutation | The radioactive decay of a nucleus and reaction of a nucleus with another particle |
How did Ernest Rutherford produce the first manmade nucleus in 1917? What did he find? | He bombarded nitrogen-14 with high speed α particles from a natural radioactive isotope of radium. He found that the formation of protons resulted from that reaction |
Define nuclear fission | the breaking of a large nucleus into smaller pieces |
During nuclear fission, the breaking (is/is not) random, forming a (small/large) number of (similar/different) products | is; large; different |
Does nuclear fission happen naturally? What is required to occur for nuclear fission to happen? | No; requires bombardment with neutrons |
When and where was the first reported instance of nuclear fission? | Germany 1939 |
Define chain reaction | repeated fission caused when the neutrons released in fission bombard other atoms |
Define nuclear fusion | the process of converting very light nuclei into heavier nuclei |
Radioactive isotopes have the same ____ as stable isotopes of the same element, but they emit ____, which can be detected | chemical properties; radiation |
List the 5 uses of radioisotopes in medicine | Locate damaged tissues in the heart, liver, and lungs; Monitor goiter and treat thyroid conditions; Monitor liver and brain tumors; Help locate obstructions to the flow of blood; Radiation therapy to damage the DNA of cancer cells |
List the 5 commercial uses of radioisotopes | Determine the thickness of films and thin metal sheets; Detect flaws in metal to be used in structures; Pest control; Food preservation; Ionization-type smoke detectors |
List the 3 "Other" uses of radioisotopes | Labeling fertilizers in studies of nutrient uptake by plants and crop growth; Investigations of digestive and milk-producing processes in cows; Studies on the growth and metabolism of animals and plants |
How can ultraviolet, X-ray, and Gamma rays impact the human body? | They can damage DNA |
List the types of radiation in order from least to most penetrating | alpha < beta < neutron < gamma |
Give the annual public dose limit of radiation (NRC) | 100 millirems |
Give the average us annual dose of radiation | 620 millirems |
Give the average nuclear service worker doses limit of radiation | 5000 millirems |