Atomic Chemistry

Vocabulary

  • [ ] Alpha Particle: A positively charged atom particle that is more massive than a beta particle or gamma radiation and is relatively slow moving; has the same combinations of particles as the nucleus of a Helium atom.
  • [ ] Beta Particle: A high-speed electron; emitted by a radioactive nucleus in beta decay.
  • [ ] Chain reaction: An ongoing process in which one fission reaction initiates the next reaction.
  • [ ] Daughter Isotope: The stable product of radioactive decay.
  • [ ] Decay Curve: A curved line on a graph that shows the rate at which radioisotopes decay.
  • [ ] Fission: A nuclear reaction in which a large nucleus breaks apart, producing two or more smaller nuclei, subatomic particles, and energy.
  • [ ] Fusion: A process in which two low-mass nuclei join together to make a more massive nucleus.
  • [ ] Gamma Radiation: Rays of high-energy short-wavelength radiation emitted from the nuclei atoms.
  • [ ] Half-Life ( Bio): The time it takes for a living tissue, organism, or ecosystem to eliminate one-half of a substance that has been introduced into it.
  • [ ] Isotopes: Different atoms of a particular element that have the same number of protons but a different number of neutrons.
  • [ ] Light: One form of radiation that is visible to humans.
  • [ ] Mass Number: The total number of protons and neutrons found in the nucleus of an atom.
  • [ ] Nuclear Equation: A set of symbols that indicates changes in the nuclei of atoms during a nuclear reaction.
  • [ ] Nuclear Reaction: The process in which an atom’s nucleus changes by gaining or releasing particles or energy.
  • [ ] Parent Isotope: The isotope that undergoes radioactive decay.
  • [ ] Radiation: High-energy rays and particles emitted by radioactive sources.
  • [ ] Radioactive Dating: Determining the age of an object by measuring the amount of carbon-14 remaining in it.

Radioactive Decay: The process in which the nuclei of radioactive parent isotopes emit alpha, beta or gamma radiation to form decay products.

Atomic Theory and Radioactive Decay

The stream of high-energy particles or waves found in our environment is called natural background radiation. It has the potential to interact with atoms, creating an ion out of it. Radiation includes multiple waves like radio, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays. Although we cannot see a lot of these waves, we can see light.

Isotopes are different atoms of a particular element that have the same number of protons, but different neutrons. Since the neutrons have changed the mass number has also changed while staying a whole number. To find the mass number, we must add the atomic number with the number of neutrons.

We can also find the number of neutrons by subtracting the atomic number from the mass number.

Chemists represent isotopes by using something called standard atomic notation, which involves the chemical symbol, atomic number, and mass number. Ex: 40/19 K

Decay

Atoms can change from one element to another through radiation. Since unstable elements become stable again when losing energy they must undergo radioactive decay.

Types of Radiation

Alpha radiation is a stream of alpha particles with a positive charge. This charge is considerably larger than the other two. It’s represented as 4/ 2He or 4/ 2a because the alpha particles have the same combination of particles as Helium. The symbol shows the mass number on top and the atomic number on the bottom. This means that Alpha particles have 2 protons and 2 neutrons. Since they’re relatively slow, they aren’t as penetrative. It only takes a piece of paper to stop the alpha particles.

Beta radiation is only one electron. we use 0/ -1 B or 0/ -1 e to represent a beta particle. Electrons are so small in weight that they don’t count for the mass of the element or particle. Lightweight and fast-moving, beta particles can be stopped with a thin sheet of aluminum. During beta decay, a neutron changes into a proton and electron. This means that the electron shoots out of the nucleus, while the proton stays in the nucleus.

Gamma radiation is something that consists of rays of energy and short-wavelength radiation. It’s represented by 0/ 0 y

Half-Life

Half-Life is used to compare the rate of radioactive decay for an isotope. If the half-life is shorter, the decay rate is quicker, and the longer the half-life, the slower the decay. Ex: 800 1st half-life, 400 2nd half-life, 200 3rd half-life.

Fission vs Fusion

Fission is when an unstable nucleus splits into two smaller, lighter elements. Fusion is the opposite, joining two smaller pieces into a larger nucleus.

Ex: 1/0 n + 235/92U → ____ + 208/ 83 Bi + 3 1/0 n + energy

Answer: 25/ 9 F