AQA A Level Physics复习笔记8.3.2 Decay Equations
Changes in N and Z by Radioactive Decay There are four reasons why a nucleus might become unstable, and these determine which decay mode will occur Too many neutrons Decays through beta-minu...
IB DP Maths: AA HL复习笔记4.6.3 Standardisation of Normal Variables
Standard Normal Distribution What is the standard normal distribution? The standard normal distribution is a normal distribution where the mean is 0 and the standard deviation is 1Why is the standa...
AQA A Level Physics复习笔记8.3.1 Nuclear Instability
Nuclear Stability Graph The most common elements in the universe all tend to have values of N and Z less than 20 (plus iron which has Z = 26, N = 30) Where: N = number of neutrons Z = number...
AQA A Level Physics复习笔记8.2.4 Applications of Radioactivity
Radioactive Dating The isotope carbon-14 is commonly used in radioactive dating It forms as a result of cosmic rays knocking out neutrons from nuclei, which then collide with nitrogen nuclei...
AQA A Level Physics复习笔记8.2.3 Half-Life
Half-Life Half-life is defined as: The time taken for the initial number of nuclei to halve for a particular isotope This means when a time equal to the half-life has passed, the activity of...
AQA A Level Physics复习笔记8.2.2 Exponential Decay
Exponential Decay In radioactive decay, the number of undecayed nuclei falls very rapidly, without ever reaching zero Such a model is known as exponential decay The graph of number of...
Edexcel IGCSE Chemistry 复习笔记 1.9.1 Explaining Conductivity
Edexcel IGCSE Chemistry 复习笔记 1.9.1 Explaining Conductivity Conductivity of Covalent Compounds Electric current is the flow of charged particles This usually refers to electrons, but it c...
AQA A Level Physics复习笔记8.2.1 Radioactive Decay
Radioactive Decay Radioactive decay is defined as: The spontaneous disintegration of a nucleus to form a more stable nucleus, resulting in the emission of an alpha, beta or gamma particle Ra...
Edexcel IGCSE Chemistry 复习笔记 1.8.1 Metallic Bonding
Edexcel IGCSE Chemistry 复习笔记 1.8.1 Metallic Bonding Metallic Bonding Metal atoms are held together strongly by metallic bonding Within the metal lattice, the atoms lose their valence ele...
