CIE A Level Chemistry复习笔记1.1.5 Isotopes
Isotopes: Basics Isotopes are atoms of the same element that contain the same number of protons and electrons but a different number of neutrons The symbol for an isotope is the chemical symbol (or...
CIE A Level Chemistry复习笔记1.1.4 Atomic & Ionic Radius
Atomic & Ionic Radius Atomic radius The atomic radius of an element is a measure of the size of an atom It is half the distance between the two nuclei of two covalently bonded atoms of the same...
CIE A Level Chemistry复习笔记1.1.3 Determining Subatomic Structure
Determining the Subatomic Structure of Atoms & Ions An atom is neutral and has no overall charge Ions on the other hand are formed when atoms either gain or lose electrons, causing them to beco...
CIE A Level Chemistry复习笔记1.1.2 Mass, Charge & Subatomic Particles
Mass & Charge Distribution The mass of an atom is concentrated in the nucleus, because the nucleus contains the heaviest subatomic particles (the neutrons and protons) The mass of the electron ...
CIE A Level Chemistry复习笔记1.1.1 Particles in the Atom & Atomic Structure
Structure of an Atom All matter is composed of atoms, which are the smallest parts of an element that can take place in chemical reactions Atoms are mostly made up of empty space around a very smal...
CIE A Level Biology复习笔记19.3.2 Using GMOs in Agriculture
GMOs in Food: Social & Ethical Implications The genetic modification of microorganisms for the production of medicines, antibiotics and enzymes raises little debate compared to the use of genet...
CIE A Level Biology复习笔记19.3.1 Genetically Modified Organisms in Agriculture
Genetic Engineering: Use in Agriculture Genetic engineering is a technique used to deliberately modify a specific characteristic (or characteristics) of an organism The technique involves removing ...
CIE A Level Biology复习笔记19.2.4 Gene Technology in Medicine
Social & Ethical Considerations The use of gene technology (genetic screening and gene therapy) in medicine is becoming more common Genetic screening in medicine is being used to: Allow people ...
CIE A Level Biology复习笔记19.2.3 Gene Therapy
Gene Therapy Gene therapy involves using various mechanisms to alter a person's genetic material to treat, or cure, diseases As scientists gain a better understanding of the human genome and theref...
