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495 results for “electron”
A full outer shell is stable; electron affinity is how strongly an atom pulls an extra electron — high on the right, low on the left. Groups VII and VIII: gainers and the unreactive. General Science 3.1 The periodic tabl…
…e comes from Every atom has a nucleus containing positively charged protons, surrounded by negatively charged electrons. In a neutral atom the numbers are equal, so the charges cancel exactly and the atom shows no charge…
Atoms are neutral until electrons move; a positive body has lost electrons, and charge is conserved. Lesson 1 introduced charge. This lesson slows down on the atom and on conservation. Physics 3.1 Electrostatics Lesson 1…
Electron affinity measures how strongly an atom attracts an extra electron; halogens have the largest values. Successive ionisation energies. Chemistry 1.5 Periodicity Ionisation energy is about losing an electron. Elect…
Pre-Technical Studies Meaning of data and information in an electronic device Importance of data in an electronic device Threats to data: virus and unauthorised access Techniques of securing data: passwords and antivirus…
…emoved first, leaves the opposite sign and a stronger charge. Charging by friction, and that conductors allow electrons to flow. Physics 3.1 Electrostatics Friction charges insulators. To charge a metal sphere you need a…
…cations of the CRO. Physics 2.3 Thermionic emission and its applications X-rays are produced when fast-moving electrons are suddenly stopped by a metal target. The X-ray tube uses thermionic emission to make the electron…
How electron arrangement places every element, and why some atoms give electrons away while others take them. Nothing. The structure of the atom is built up here from the beginning. General Science 3.1 The periodic table…
… anything. Three elements, three completely different levels of caution - and all of it follows from how many electrons sit in the outer shell. Chemical family A chemical family is a group of elements in the same vertica…
…ube. Physics 2.3 Thermionic emission and its applications Cathode rays are used wherever a controlled beam of electrons is needed. Old television and computer screens, the cathode ray oscilloscope, electron microscopes, …
Electrical Technology Meaning and function of a power supply in an electronic system Direct current sources: cells, batteries and solar cells Alternating current mains supply and the need for conversion Types of power su…
A neutron becomes a proton plus an electron; Z rises, A does not. Alpha radiation close up. Physics 2.2 Radioactivity and Stability of Isotopes A beta particle is an electron — but it does not come from the electron shel…
… The Cell The last lesson left a list of parts you could not see. This lesson is that list, photographed with electrons. A Kenyan school does not own an electron microscope. Hospitals and universities that do - and the d…
One outer electron, a knife-soft metal, and a reaction that gets more violent as the atom gets larger. What a chemical family is, and that group I atoms each have one outer electron. General Science 3.2 Chemical Families…
Heat can break a covalent bond in pure silicon, freeing an electron and leaving a hole in equal numbers. Covalent bonds in pure silicon. Electrical Technology 4.1 Semiconductor Theory A perfect silicon crystal at absolut…
…ding in an electrolyte - a liquid or paste that conducts by ions. A chemical reaction at the electrodes frees electrons. Those electrons will not jump through the liquid; they travel through a wire if you give them one. …
The difference between data and information on an electronic device, and why marks, money and names stored on phones and lab computers must stay safe. Grade 7 computer concepts: computer, data and information. Pre-Techni…
A metal transfers outer electrons to a non-metal; the ions then attract. Why atoms form bonds. Chemistry 1.4 Chemical Bonding Ionic bonding is a two-step story: transfer, then attraction. Learners who skip the second ste…
Among the first 20, metals have 1, 2 or 3 outer electrons. Use Na, Mg, Al, K and Ca. Skip iron: Z=26 is outside the first 20. Aluminium sufurias; sodium in salt. Dot diagrams and the 2, 8, 8, 2 rule. Integrated Science 1…
…acuole and large mitochondria. It can be used on living material, which turns out to matter a great deal. The electron microscope An electron microscope uses a beam of electrons instead of light, and electromagnets inste…
… silicon into the most useful material in modern technology. The previous lesson. Physics 3.3 Introduction to electronics Pure silicon is not a very good semiconductor. It conducts a little, unpredictably, and depends en…
…Kenya this work is done by the Central Depository and Settlement Corporation, the CDSC, which keeps shares in electronic form in a CDS account and settles trades safely and quickly. Our question: How are transactions on …
… Bonding A neon atom in air does almost nothing. A sodium atom in air tarnishes at once. Both have nuclei and electrons. The difference is the outer shell. Full outer shell A full outer shell is two electrons in the firs…
Hydrogen sits above group I because it has one electron, but it is a non-metal that can also behave like a halogen. The first twenty placed. Chemistry 1.3 The Periodic Table Every wall table puts H above lithium. Learner…
…ends on what kinds of atoms are involved. Ionic bonding Ionic bonding occurs between a metal and a non-metal. Electrons are transferred from the metal atom to the non-metal atom. Both then have full outer shells - but bo…
A pentavalent donor in the silicon lattice leaves a spare free electron - the negative majority carrier. Doping: making extrinsic semiconductors. Electrical Technology 4.1 Semiconductor Theory This lesson is only N-type.…
Why the table is shaped as it is, and reading an element from its address. Sub-strand 1.2 on atoms and electron arrangement. Chemistry 1.3 The Periodic Table The periodic table is not a list. It is an arrangement, and th…
Explain how electronic media, the internet and applications preserve Hadith today. Modes of preservation of Hadith. Islamic Religious Education 1.3 Ulum al- Hadith: Contemporary collections of Hadith Modern technology ha…
…afety rules and why each exists, the setup procedure in order, ergonomics, and reusing working equipment from electronic waste. The previous lesson. Computer Studies 1.7 Computer setup ### The tools Screwdrivers - a Phil…
Two outer electrons, so less reactive than group I, but still a family that burns, fizzes and makes hard water. Alkali metals with water, and that losing two electrons is harder than losing one. General Science 3.2 Chemi…
…ties of cathode rays. Physics 2.3 Thermionic emission and its applications The cathode ray tube (CRT) uses an electron beam inside a glass tube. The beam is focused, deflected by electric or magnetic fields and made to h…
An electron has charge -1, occupies shells around the nucleus, and has tiny relative mass (about 1/1840). Lithium shows two inner electrons and one outer. Proton and neutron in the nucleus. Integrated Science 1.1 Structu…
General Science Types of microscopes; differences between light and electron microscopes Cell structure and functions Levels of cell organisation explain the differences between light and electron microscopes describe th…
…The cathode ray oscilloscope and the X-ray tube are two important applications of thermionic emission and the electron beam. Between them they help us measure electricity, see inside the body and check the safety of mach…
Draw sodium transferring its outer electron to chlorine, then show Na+ and Cl- with full shells. Ionic charges and formulae. Chemistry 1.4 Chemical Bonding A dot-and-cross diagram shows which atom provided each outer ele…
Atoms that still need two or three electrons share two or three pairs; carbon dioxide is two double bonds, not a giant structure. Covalent single bonds: hydrogen, water, ammonia and methane. General Science 3.3 Chemical …
First ionisation energy is the energy needed to remove one electron from a gaseous atom. Ionic radius versus atomic radius. Chemistry 1.5 Periodicity To turn a sodium atom into Na + you must pull the outer electron off. …
First ionisation energy falls down a group because the outer electron is further out and more shielded. First ionisation energy. Chemistry 1.5 Periodicity Lithium's first IE is high for a metal. Potassium's is lower. Cae…
Mass on a beam or electronic balance (kg, g). Weight on a spring balance (N). Zero, dry pan, no overload. Using a laboratory thermometer. Integrated Science 1.3 Laboratory apparatus and instruments People say "weight" wh…
Every periodic trend is decided by how tightly the nucleus holds the outer electron. Trends across a period. Chemistry 1.5 Periodicity The two overview lessons showed the patterns. This lesson names the three causes that…