C H A P T E R 7 Site-to-Site VPN Configuration Examples A site-to-site VPN protects the network resources on your protected networks from unauthorized use by users on an unprotected network‚ such as the public Internet. The basic configuration for this type of implementation has been covered in Chapter 6‚ “Configuring IPSec and Certification Authorities.” This chapter provides examples of the following site-to-site VPN configurations: • • • • • Using Pre-Shared Keys Using PIX Firewall
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the atomic mass scale) of the fundamental particles - protons‚ neutrons and electrons. * State that atoms have a dense positively charged nucleus (consisting of protons and neutrons) around which move negatively charged electrons. * State that an element is identified by its atomic number (Z)‚ which is the number of protons in the nucleus and determines the number of electrons in a neutral atom of the element. *
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Element name-Helium Element Symbol-He Atomic number-2 Group name or number- Part of the noble gases in group 18 Atomic mass (to nearest thousandth)-4.003 Number of protons-2 Number of neutrons-2 Number of electrons-2 Number of valence electrons-2 List of isotopes-He3 and He4 Electron Configuration-1s2 Discovered By-Pierre Janssen Year discovered-1868 Circumstances of discovery- Janssen discovered helium in 1868 when he was looking in a telescope when he found the yellow spectrum lines of helium. It
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photosynthesis and precipitation: Respiration- oxygen is taken in and carbon dioxide and water are given out Oxidation- a loss of electrons and a increase in oxygen Photosythesis- converting light energy into glucose Precipitation- to create a solid into a solution Protons neutrons and electrons : Protons are positive with a mass of 0.99 Neutrons have no charge and have a mass of 1 Electrons have a negative charge and a mass of 0.0005 What is PH: A scale that measurers how acidic or alkaline a substance if
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two atoms Valence electron – the outer most shell electrons There are three types of chemical bonding i. Ionic bond: ________________________________________ ii. Covalent bond: _____________________________________ iii. Dative Covalent bond: _______________________________ 1.1.1 LEWIS DOT SYMBOL A shorthand to represent the valence electron of an atom. The element symbol surrounded by dots that represent the valence electrons. The Lewis structures for
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1st Step Basic router configuration commands Continue with configuration dialog? [yes/no]: n Press RETURN to get started! Router>en // to enter from USER mode to Privilege mode use this command (en = enable) & press enter Router#conf t // to enter from PRIVILAGE mode to CONFIGURATION mode use this command (en = enable) & press enter Enter configuration commands‚ one per line. End with
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(1) 2.Calculate the number of lines when an electron jumps from 6th level to 2nd level. (1) 3. If two discharge tubes A and B are filled with Hydrogen and oxygen respectively‚ will the electrons and gaseous cations be the same? Justify your answer. (1) 4. Which
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Classification of matter • All the objects and substances that we see in the world are made of matter. • This matter can be classified according to whether it is a mixture or a pure substance. • A mixture is a combination of two or more substances‚ where these substances are not bonded (or joined) to each other and no chemical reaction occurs between the substances. Examples of mixtures are air (a mixture of different gases) and cereal in milk. • The main characteristics
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Hall effect was discovered in 1879 by Edwin Herbert Hall while working on his doctoral degree at the Johns Hopkins University. The Hall effect is due to the nature of current in a conductor. Current consists of the movement of many small carriers(electrons‚ holes or both). Moving charges experience the Lorentz force when a magnetic field is present that is perpendicular to their motion. In the absence of the magnetic field‚ the charges follow ‘line of sight’ paths between collisions with impurities
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|8 | |What is an orbital? |9 | |Discovery of electron‚ proton and neutron |12 | |Chapter 7 Chemical bonding: ionic bonding
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