Welcome to class!
In today’s class, we will be talking about nuclear chemistry. Enjoy the class!
- Types and Nature of Radiation
- Half-life as a measure of the stability of the nucleus.
Nuclear Chemistry is an aspect of chemistry that deals with nuclei of atoms.
This is the spontaneous emission of radiation by a radioactive element such as Thorium, Uranium etc.
- Spontaneously and continually emitting of radiation by a radioactive element
- Temperature and pressure do not affect radioactivity
- The radiation can pass through opaque objects
- It affects photographic plates
- It causes ionization of gases through which it passes.
- It causes fluorescence of certain substance
- It releases a large amount of energy.
Types of radiation
There are three (3) types of radiation
Characteristics of alpha-rays
- They are Helium in nature 42He with 4 atomic mass and 2 atomic number
- Alpha rays are fast-moving streams of positively charges
- They are deflected toward the negative plate in an electrostatic field
- They have a very low penetrating power
- They can be absorbed/stopped by a thin sheet of paper on Aluminium foil
- They cause fluorescence of some materials e.g Zinc Sulphide
Characteristics of beta-rays
- They are electron in nature with a mass number of zero and charge of -1 (oe)
- They are a fast-moving stream of electrons
- They can penetrate than alpha rays
- State two (2) properties of ά, β, and Y rays each.
- What do you know about radioactivity?
Detection of radiation
The radiation can be detected by using the following devices.
- Geiger Miller Counts
- Scintillation counter
- Diffusion cloud chamber
The half-life of a radioactive element is the time taken for half of the actual number of atoms in a given substance or radioactive element to decay.
The spontaneous disintegration/decay of the nucleus of an element is due to its instability.
The neutron-proton ratio determines the stability of an element.
This varies between unity for the lighter elements and a value of about 1.5 for the heavier element with atomic numbers around eighty.
N.B. Atoms with a neutron – protons less than 1 or greater than 1.5 tends to be unstable.
- State two methods through which radiation can be detected.
- What is half-life as a measure of the stability of the nucleus?
- Define the term nuclear chemistry
- Define the term radioactivity.
- Explain the term radioisotopes
- Give an account of the uses of radioisotopes.
New School Chemistry by O.Y, Ababio pages 299-304.
- ____ is an example of radiation (a) Aloha (b) Carbon (c) Uranium (d) Nucleus.
- Alpha particle was deflected towards negative plate while Beta deflected toward (a) Neutral plate (b) Negative plate (c) Zero plate (d) positive plate
- The following caused fluorescence of matter except for (a) Alpha (b) Beta (c) Gamma (d) X-ray
- In the above diagram, Z represents (a) Alpha (b) Beta (c) Gamma (d) Radioactive
- Find the half-life of a radioisotope element which was found to be 120g initially and later changed to 15g in 24 hours
- State the three main type of radiation with their properties each.
In our next class, we will be talking about Nuclear Reactions. We hope you enjoyed the class.
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