Which one of the following molecules has tetrahedral geometry? A. CF4 B. XeF4 C. BF3 D. NH3 E. AsF5 63. A molecule with 3 single bonds and 0 lone pairs of electrons is predicted to have which type of molecular geometry? A. Trigonal planar B. Trigonal pyramidal C. Bent D. Trigonal bipyramidal E. Linear 64. A central atom with 4 electron pairs (single bonds and/or lone pairs of electrons) could have which of the following molecular geometries?
Unit 2 ( Isotopes Problem Set 2-2 1. Which of the following are isotopes of element X, with atomic number of 9: [pic],[pic],[pic], and [pic]. 2. For each of the following isotopes, write the nuclear symbols: a. Cu-63, Cu – 65 b. C-12, C-14 c. Mg-24, Mg-25, Mg-26 d. Ne-20, Ne-21, Ne-22 3. Verify that the atomic mass of magnesium is 24.31 amu, given the following information: [pic], mass = 23.985042 amu; percent abundance = 78.99% [pic], mass = 24.985837 amu; percent abundance = 10.00% [pic], mass = 25.982593 amu; percent abundance = 11.01% 4.
The process of changing one element into another is called transmutation. The two main ways that a transuranic nucleus can be produced is by bombarding its nucleus with ions or neutrons. These ions or neutrons can be captured by the target nucleus and produce heavier nucleus. Transuranic element 1: U-238 is bombarded with neutrons it can be converted to U-239 which then undergoes beta decay to produce neptunium and plutonium. Pu-239 is changed to americium-241 by neutron
Which pairs will react from an ionic compound? Chlorine and oxygen Nitrogen and Lithium b. Which pairs will react from a molecular compound? Flour nine and Argon c. Which pairs will not react to form a compound? Aluminium and potassium 7) A certain particle was found to contain sixteen protons and eighteen electrons.
1.23 C. 5.74 X 10-4 D. 0.658 _____ 14. Which of the following is true for the following voltaic cell? Zn (s) ( Zn2+(aq) (( Cr3+ (aq) ( Cr (s) A. The electrons flow from cathode to the anode. B.
Pb (NO3) 2 10. A compound is 42.3 % C, 5.94 % H, 32.9 % N, and 18.8 % O and has a molecular mass of 425.25 g/mol. Calculate the empirical and molecular formula. C15H25N10O5 11. How many moles of Al2O3 are produced by the reaction 200. g Al?
(1 point for each molecule) The central atom is C. 2. How many atoms are bonded to the central atom? (1 point for each molecule) There are two atoms bonded to the central atom. 3. How many lone pairs of electrons are on the central atom?
N05/4/PHYSI/SPM/ENG/TZ0/XX+ The mass of an atom of the isotope strontium-92 (92Sr) is of the order of A. B. C. D. 10–23 kg. 10–25 kg. 10–27 kg. 10–29 kg.
OCR B CHEMISTRY F331 (Unit 1) Revision Guide 2014 Formulae, equations and amount of substance | Key Terms (a). * Atomic Number: Atomic number is the number of protons in the nucleus. * Mass Number: Mass number is defined as the sum of the numbers of protons and neutrons in the atom’s nucleus. * Isotopes: Atoms with the same number of protons but different number of neutrons are called isotopes; they therefore have different masses. * Avogadro’s constant: The number of toms per mole is called the Avogadro’s constant.
Your friend says that what makes one element distinct from another is the number of electrons about the atomic nucleus. Do you agree wholeheartedly, partially, or not at all? Explained • NO • What makes one element distinct from another is the number of protons in the nucleus. Hydrogen has 1, gold has 79, uranium has 92, etc. Not electrons.