in a Bohr hydrogen atom from n = 2 to n = 3 is __________ J. A) 3.00 × 10-19 B) 4.60 × 1014 C) 4.00 × 10-19 D) -7.90 × 10-19 E) -3.00 × 10-19 6. When the electron in a hydrogen atom moves from n = 8 to n = 2 light with a wavelength of __________ nm is emitted. A) 389 B) 657 C) 93.8 D) 411 E) 487 7. The wavelength of an electron whose velocity is 1.7 × 104 m/s and whose mass is 9.1 × 10-28 g is __________ m. A) 12 B) 4.3 × 10-8 C) 4.3 × 10-11 D) 2.3 × 10-7 E) 2.3 × 107 8. There are
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the statement or answers the question. 1) Which one of the following is correct? A) ν ÷ λ = c B) ν = cλ 1) C) νλ = c D) λ = c ν E) ν + λ = c 2) The photoelectric effect is __________. A) a relativistic effect B) the ejection of electrons by a metal when struck with light of sufficient energy C) the darkening of photographic film when exposed to an electric field D) the production of current by silicon solar cells when exposed to sunlight E) the total reflection of light by metals
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between the Nucleus and the valence electrons increases with every new period; a new electron shell is added. This increases the atomic size which makes the valence electrons more further from the nucleus. This decreases the attraction between the nucleus and the valence electrons. b) Since there are more filled inner shells now‚ these provide a stronger shielding effect for the valence electrons; effectively reducing the attraction between the valence electrons and the nucleus. c) Although the
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ICSE Chemistry(Part-I) Goyal Brothers Prakashan (Chapter 4) 4. UTSE study materials given below 3. Atomic Structure : Fundamental particles of atom(electron‚ proton‚ neutron)‚ Discovery of Nucleus by Gold foil experiment‚ Rutherford’s model of atom and its demerits‚ Bohr’s model of atom atomic number‚ mass number‚ isotopes‚ isobars‚ Distribution of electrons in shells‚ Valency Reference : 1. NCERT class IX text book(Chapter 4) 2. . Foundation Science(Chemistry) :Class IX A. K. Singh ( Bharati Bhawan)
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What is Krypton? Some might say it is the planet Superman is from‚ but it is actually a chemical element. Krypton is one of the rarest gases on Earth which makes it very expensive. It can also be found in Mars’s atmosphere‚ but only makes up 0.3 parts of a million. Krypton was discovered in 1898 by Morris Travers and Sir William Ramsey. It was named after the Greek word‚ kryptos‚ which means “hidden”. The basic facts: Noble gases carry the trait of not reacting with many elements and Krypton
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Kull Key Chemistry 105 Practice Test 3 Spring 2007 Student: ________________________ The actual test will have 15 multiple choice‚ select 12 for grading‚ and 5 or 6 workout problems. There are no work-out problems here‚ bur the types of required computations are seen in the multiple choice problems here. I will place an updated equation sheet on the web by Wednesday morning‚ as well as post the answer key. 1 Who proposed a model that successfully explained the photoelectric effect? A
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9.1 Orbitals and Theories of Chemical Bonding 1. Which one of the statements concerning valence bond (VB) and molecular orbital (MO) bond theories is correct? a) MO theory predicts that electrons are localized between pairs of atoms. b) In VB theory‚ bonding electrons are delocalized over the molecule. c) MO theory accurately describes bonding in O2 and NO‚ VB theory does not. d) VB theory can describe molecular bonding in excited states. e) MO theory is used to accurately predict
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discussions Table of Contents* [A] Lecture [1] Thermodynamics [2]Energy [3]Enthalpy [4]Hess’s Law [5]Determining Enthalpy [6]Heat Capacity [7]Calorimetry [8] Entropy [9] Gibb’s Free Energy [10] Waves [11] Quantum Theory [12] Quantum Numbers [13] Electron Configuration [14] Periodic Table [15] Periodic Trends KSev [16] Chemical Bonding [17] Formal Charge [18] Resonance Structure [19] Bonds [20] VSEPR [22] Valence Bond Theory [22] Molecular Orbital Theory [B]Lab [1] Corrosion [2] Oxidation Reduction Reactions
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unstable isotopes lose energy by emitting ionising particles or radiation through the process of radioactive decay. Ernest Rutherford and later Paul Villard discovered the three types of radiation: -radiation (nucleus of helium atom); -radiation (electron); and -radiation. (a) (i) Define the term isotope. Answer: Isotopes are atoms having the same number of protons / proton number / atomic number / of the same element but have different number of neutrons / different mass numbers / different
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Just so you know compounds exist in only three noble gases—krypton‚ radon‚ and xenon. Chemists have yet to make any compounds of helium‚ neon‚ or argon. The reasons that Noble Gases are not very reactant is because they have a full set of 8 valence electrons. The discovery of neon was an unintentional discovery. Its discovery will not be fully understandable unless told the background story of the research of air. It took humans much time to get a full understanding of air. At one point‚ philosophers
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