highly efficient and selective excitation behavior for the studied molecular systems. On the other hand‚ it was demonstrated that the molecular excitation is a very complex conjunction of different one-electron orbital depopulation-population
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Effect of ions on living organisms (24 marks) An ion is a charged atom or molecule. This is because it does not have an equal amount of protons and electrons‚ therefore giving the atom an overall charge. An example of an ion is ‚ this is sodium and the plus sign represents an overall positive charge. Ions are very important to living organisms as they are essential for life‚ they play an important role within the cell allowing mechanisms within the living organisms such as respiration‚ to take
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Week 2 Quiz Which of these is NOT one of the four general categories of cells that make up the human body? collagen cells muscle cell neuron connective tissue cell epithelial cells What is the term for the developmental process that leads to specialized cell types? homeostasis differentiation positive feedback genomics acclimatization If a person begins to sweat upon entering a hot room but continued sweating is able to keep the body temperature constant‚ which of these best
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Krypton (noble gas) and Rubidium (Group I metal) Kr has a simple molecular structure and Rb has a giant metallic structure. Larger amount of energy is needed to overcome the stronger electrostatic attraction between Rb+ and its mobile electrons than the weaker van der Waals’ forces between Kr atoms . Hence‚ boiling point of Rb is higher than that of Kr. b) AlF3 and PF3 AlF3 has a giant ionic structure and PF3 has a simple molecular/ covalent structure. Larger amount of energy
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conventional x-ray tube the electron beam accelerates from a fila ment to an anode‚ where it decelerates rapidly at the anode and emits x-rays (shown schematically in Fig. 2). A different approach is to accelerate (or decelerate) the particle by passing it through a magnetic field. This is what really happens in an accelerator. When the particles curve in the magnetic field‚ x-rays are emitted. These x-rays are very collimated. The effective source is very small because the electrons can be focused down
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Rutherford was investigating physics everyday he tried lots of experiments. Rutherford showed that gamma rays were a type of X-ray‚ and that the alpha and beta rays were tiny particles of matter. Rutherford then showed that the beta particles were electrons. In 1908 Rutherford demonstrated and made an airtight glass tube with very thin walls‚ and filled it with the radioactive radium emanation. Alpha particles could penetrate the thin walls of the tube and were collected in a second tube. Rutherford
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3 Name: Flame Tests & Electron Configuration Pre-Laboratory Questions and Exercises Due before lab begins. Answer in the space provided. 1. Write electron configuration for the alkali metals Li‚ Na‚ K‚ and Rb. Li ____He 2s1_____________________________________________ Na ____Ne 3s1______________________________________________ K _______Ar 4s1___________________________________________ Rb _______Kr 5s1___________________________________________ 2. Write the electron configuration for strontium
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of Radiation and Radioactivity Introduction: Radiation can be defined as the propagation of energy through matter or space. It can be in the form of electromagnetic waves or energetic particles. Ionizing radiation has the ability to knock an electron from an atom‚ i.e. to ionize. Examples of ionizing radiation include: • alpha particles • beta particles • neutrons • gamma rays • x-rays Non-ionizing radiation does not have enough energy to ionize atoms in the material it interacts with. Examples
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example electron‚ proton and many more. Electric charge is the property responsible for electric forces which acts between nucleus and electron to bind the atom together. Charges are of two kinds (i) negative charge (ii) positive charge Electrons are negatively charged particles and protons‚ of which nucleus is made of‚ are positively charged particles. Actually nucleus is made of protons and neutrons but neutrons are uncharged particles. electric force between two electrons is same
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non-covalent bonding. Covalent bonding involves the pairing of electrons that are shared between atoms‚ whereas non-covalent bonding involves the attraction of electromagnetic forces between atoms. Covalent bonds are strong and non-covalent bonds are weak. Both covalent and non-covalent bonds relate in a sense of stability as covalent bonds are most stable when its outmost electron shell filled‚ typically octet (or eight electrons)‚ and non-covalent bonds are stable when they have a strong electronegativity
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