Chem 3 HW Ch. 2

7) Identify the elements in each chemical formula, and give the number of atoms of each element. a) NaCN (sodium cyanide) b) H2S (hydrogen sulfide) c) C2H6 (ethane) d) SnF2 (stannous fluoride) e) CO (carbon monoxide) f) C3H8O3 (glycerol)

a) 1 sodium, 1 carbon, 1 nitrogen b) 2 hydrogens, 1 sulfur c) 2 carbons, 6 hydrogens d) 1 tin, 2 fluorines e) 1 carbon, 1 oxygen f) 3 carbons, 8 hydrogen, 3 oxygens

15) Magnesium has three isotopes that contain 12, 13, 14 neutrons. For each isotope give the following information: a) the number of protons b) the number of electrons c) the atomic number d) the mass number e) write the isotope symbol of each isotope

a) 12, 12, 12, 24, 24/12Mg b) 12, 12, 12, 25, 25/12Mg c) 12, 12, 12, 26, 26/12Mg

61) How many protons, neutrons, and electrons are contained in each element? a) 27/13Al b) 35/17Cl c) 34/16S

a) 13, 14, 13 b) 17, 18, 17 c) 16, 18, 16

71) Give the total number of electrons, the number of valence electrons, and the identity of the element with each electronic configuration. a) (1s^2)(2s^2)(2p^6)(3s^2)(3p^4) b) (1s^2)(2s^2)(2p^3)

a) 16 electrons, 6 valence electrons, sulfur b) 8 electrons, 6 valence electrons, oxygen

12) How many protons, neutrons, and electrons are contained in each atom with the given atomic number and mass number? a) Z = 17, A= 35 b) Z = 14, A = 28 c) Z = 92, A = 238

a) 17, 18, 17 b) 14, 14, 14 c) 92, 146, 92

10) Identify the element with each atomic number, and give the number of protons and electrons in the neutral atom: a) 2 b) 11 c) 20 d) 47 e) 78

a) 2, Helium (He), 2, 2 b) 11, Sodium (Na), 11, 11 c) 20, Calcium (Ca), 20, 20 d) 47, Silver (..), 47, 47 e) 78, Platinum (...), 78, 78

11) For the given atom: a) determine the number of protons and neutrons b) give the atomic number and the mass number c) identify the element

a) 4 protons and 5 neutrons b) atomic number 4, mass number 9 c) beryllium

35) Give the following information about the atom shown: Picture contains a bundle of 5+ 6reg particles. a) the number of protons and neutrons in the nucleus b) the atomic number c) the mass number d) the number of electrons in the neutral atom e) the element symbol

a) 5 protons and 6 neutrons b) 5 c) 11 d) 5 e) B

14) For each atom give the following information [1] the atomic number; [2] the mass number; [3] the number of protons; [4] the number of neutrons; [5] the number of electrons. a) 13/6C b) 121/51Sb

a) 6, 13, 6, 7, 6 b) 51, 121, 51, 70, 51

9) An element has nine protons and 10 neutrons in the neutral atom. a) How many electrons are present in the neutral atom? b) What is the atomic number of this element? c) Identify the element

a) 9 b) 9 c) fluorine

13) What is the mass number of an atom that contains a) 42 protons, 42 electrons, and 53 neutrons? b) 24 protons, 24 electrons, and 28 neutrons?

a) 95 b) 52

37) Selenium is a micronutrient necessary for certain enzymes that block unwanted oxidation reactions. Selenium is also needed for proper functioning of the thyroid gland. Answer the following questions about the element selenium. a) What is its element symbol? b) To what group number and period does selenium belong? c) Is selenium a main group element, transition metal, or inner transition metal? d) how many valence electrons does selenium contain? e) draw an isotope symbol for a selenium atom that contains 46 neutrons in the nucleus.

a) Se b) group number 6A (16) and period 4 c) main group element d) 6 e) 80/34Se

17) The element cobalt is a micronutrient present in vitamin B12. a) What is the atomic number and atomic weight of cobalt? b) how many protons and electrons does a neutral cobalt atom contain?

a) atomic number 27 and atomic weight 58.93 amu b) 27 protons and 27 electrons

49) Identify the element that fits each description. a) an alkali metal in period 6 b) a transition metal in period 5, group 8 c) a main group element in period 3, group 7A d) a halogen in period 2

a) cesium b) ruthenium c) chlorine d) fluorine

67) What element(s) in the first three periods fit each description? a) the element contains five electrons in the 3p orbitals. b) there is one valence electron. c) the element contains four electrons in the second energy level.

a) chlorine b) hydrogen, lithium, sodium c) carbon

45) Give the name of the elements in each group of three element symbols a) Au, At, Ag b) N, Na, Ni c) S, Si, Sn d) Ca, Cr, Cl

a) gold, astatine, silver b) nitrogen, sodium, nickel c) sulfur, silicon, tin d) calcium, chromium, chlorine

83) Rank the atoms in each group in order of increasing size. a) boron, carbon, neon b) calcium, magnesium, beryllium c) silicon, sulfur, magnesium d) krypton, neon, xenon

a) neon < carbon < boron b) beryllium < magnesium < calcium c) sulfur < silicon < magnesium d) neeon < krypton < xenon

51) Give all of the terms that apply to each element: [1] metal; [2] nonmetal; [3] metalloid; [4] alkali metal; [5] alkaline earth element; [6] halogen; [7] noble gas; [8] main group element; [9] transition metal; [10] inner transition metal. a) sodium b) silver c) xenon d) platinum

a) sodium: metal, alkali metal, main group element b) silver: metal, transition metal c) xenon: nonmetal, noble gas, main group element d) platinum: metal, transition metal