1. The correct answer for the following operation (4.123 × 0.12) + 24.2 is __________ A) 24.69476 B) 24.695 C) 24.70 D) 24.7 E) 25 2. Round 1106 to three significant figures. A) 110 B) 111 C) 110.6 D) 1110 E) 1.10 × 10³ 3. 2.505 × 10² inche / 1.75 inches is equal to (watch your units!) A) 143.14 in. B) 438 in. C) 143.1 in. D) 143 in. E) 143 4. Which one of the following statements about atomic structure is false? a) An atom is mostly empty space. b) Almost all of the mass of the atom is concentrated in the nucleus. c) The protons and neutrons are tightly packed in the nucleus. d) The number of protons and neutrons is always the same in the neutral atom. e) The electrons are located outside of the nucleus. 5. Which particle has the smallest mass? A) neutron B) proton C) electron D) helium nucleus E) hydrogen atom 6. A 8.237 g sample containing only lead, carbon, and hydrogen was burned in an oxygen-rich environment. The products of the combustion were 8.965 g CO?(g) and 4.587 g H?O(g). What is the empirical formula of the compound? A) C?H??Pb B) C?H??Pb C) C?H??Pb D) C?H??Pb? E) C?H??Pb? 7. How fast does light travel in a nanosecond? A) about 1 mile B) about 1 inch C) about 1 foot D) about 1 meter E) about 1 km 8. Calculate the energy change when an electron in a hydrogen atom undergoes a transition from n=6 to n=1. A) 1.8166 × 10?¹? J B) 1.8166 J C) -1.8166 × 10?¹? J D) -2.1193 × 10?¹? J E) 2.1193 J
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123 by 0.12 to get 0.49476. Since we are limited to 2 significant figures, the result is 0.49. Show more…
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Amber B.
1. Ernest Rutherford first transmuted one element into another by the bombardment of nitrogen-14 with alpha particles, resulting in oxygen-17 being produced. What particle was emitted in that process? A. Hydrogen nucleus B. a neutron C. an alpha-particle D. a beta-particle 2. Given the nuclear equation: H + X -> Li + He. The particle represented by X is A. 9Li B. 9Be C. 10Be D. 10C 3. Atoms of one element are converted to atoms of another element through A. Fermentation B. Oxidation C. Polymerization D. Transmutation 4. All atoms of a given element have the same _____. A. atomic mass B. mass number C. number of neutrons D. atomic number 5. In the symbol, xC x is _____. A. the number of neutrons B. the atomic number C. the mass number D. the isotope number Practice Exercise: DIRECTIONS - Complete the following nuclear transmutation equations by writing your answers on the blanks provided. A periodic table on the next page will help you answer the activity. 1. 14 7N + 4 2alpha -> _____ + 1 1p 2. 56 26Fe + 2 1H -> 4 2alpha + _____ 3. _____ + 1 0n -> 3 1H + 4 2alpha 4. 27 13Al + 4 2alpha -> _____ + 1 0n 5. 239 94Pu + _____ -> 240 95Am + 0 -1beta Evaluation: Directions: Choose the letter of the BEST answer. 1. Ernest Rutherford first transmuted one element into another by the bombardment of nitrogen-14 with alpha particles, resulting in oxygen-17 being produced. What particle was emitted in that process? A. Hydrogen nucleus B. a neutron C. an alpha-particle D. a beta-particle 2. Given the nuclear equation: H + X -> Li + He. The particle represented by X is A. 7 3Li B. 9 4Be C. 10 5B D. 10 6C 3. Atoms of one element are converted to atoms of another element through A. Fermentation B. Oxidation C. Polymerization D. Transmutation 4. All atoms of a given element have the same A. atomic mass B. mass number C. number of neutrons D. atomic number 5. In the symbol, A Z X, X is A. the number of neutrons B. the atomic number C. the mass number D. the isotope number
Sikandar B.
A naturally occurring sample of chlorine (Cl, atomic number = 17) has an atomic weight of 35.453 amu. Which of the following statements about chlorine is WRONG? Select one: A. All chlorine atoms have seventeen protons. B. Chlorine atoms have three shells of electrons. C. All chlorine atoms have a mass of 35.453 amu. D. Chlorine atoms have seven valence electrons. E. Chlorine atoms do not all have the same number of neutrons. Which of the following statements about atoms are correct? I. Almost all of the mass of the atom is due to the protons. II. An atom is more than 10,000 times larger than its nucleus. III. All atoms of the same element have the same number of protons. IV. Protons and neutrons have the same charge. V. Atoms in the same group of the Periodic Table have the same number of electron shells. Select one: A. I, III, and V. B. All of these are correct. C. II and III. D. I, II, and V. E. II, IV, and V. Which of the statements about the effective nuclear charge, Zeff, is wrong? Select one: A. The value of Zeff is smaller than the value of Z because of repulsion between electrons. B. The values of Zeff decrease on going across the periodic table from Na to Cl. C. The value of Zeff is approximately the same for the atoms in the same column of the periodic table. D. The value of Zeff for the calcium atom, Ca, Z = 20, is approximately 2+. Which is the correct short-form electron configuration for the atoms in calcium nitride? Select one: a. Ca = [Ar], N = [Ne] 2s2 2p5. b. Ca = [Ar] 4s2, N = [He] 2s2 2p3. c. Ca = [Ar], N = [Ne] d. Ca = [Ar], N = [He]. e. Ca = [Kr], N = [Ne].
Madhur L.
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