Atomic Spectra and Nuclear Radiation

Atomic Spectra

Atomic spectra are unique spectra of light that are emitted or absorbed by an atom.
The spectral lines result when electrons transition between energy levels in the atom.
A line spectrum is the pattern of spectral lines formed when light passes through a gas and is observed at high resolution.
The position of lines in atomic spectra are characteristic of the particular element and can be used to identify the element.
An emission spectrum is produced when an atom or molecule makes a transition from a high-energy state to a lower energy state and emits a photon.
In contrast, an absorption spectrum is a spectrum of electromagnetic radiation transmitted through a substance, showing dark lines or bands due to absorption of specific wavelengths.

Nuclear Radiation

Nuclear radiation refers to particles or electromagnetic waves that are released from the nuclei of unstable atoms.
Three types of nuclear radiation exist: alpha (α) particles, beta (β) particles, and gamma (ɣ) rays.
Alpha particles consist of two protons and two neutrons (like a helium nucleus) and are positively charged. They have low penetration power but can cause damage if ingested.
Beta particles are high-speed electrons emitted from the nucleus and have greater penetration power than alpha particles. However, they’re less damaging unless inhaled or ingested.
Gamma rays are electromagnetic radiation with the highest energy. These rays have no mass or charge but have extremely high penetration power, requiring thick lead or concrete to block.
Half-life is the time taken for half the radioactive nuclei in a sample to decay. It is a measure of the stability of a nucleus.
Radioactive decay is a random process at the level of single atoms, in that, according to quantum theory, it is impossible to predict when a particular atom will decay.

Uses and Detection of Nuclear Radiation

Nuclear radiation in the form of radioisotopes is used in a variety of applications in medicine, industry and scientific research.
Radiotracers can be used in medical and industrial applications to trace the path of substances through various systems.
Geiger-Muller tubes and scintillators are two commonly used devices for detecting and measuring ionising radiation.
Radiation is measured in becquerels (Bq), and exposure is measured in sieverts (Sv).
Safety measures must be in place when handling radioactive materials to protect from radiation exposure, including the use of shielding, distance and time.

Remember that understanding the properties, uses and precautions of atomic spectra and nuclear radiation could contribute towards answering examination questions thoroughly. Practice using this information to explain scenarios and solve problems within these topics.