Thomas Edison State College
General Chemistry I with Labs (CHE-121)
Section no.: OL009
Semester and year: FEB2015
Written Assignment 2: Atomic Structure and Chemical Compounds
Answer all assigned questions and problems, and show all work.
1What is the mass number of an iron atom that has 28 neutrons? (3 points)
2Calculate the number of neutrons of 239Pu. (3 points)(Reference: Chang 2.14)A = 239, Z = 94Number of neutrons = 239 – 94 = 1453Write the appropriate symbol for each of the following isotopes: (a) Z = 11, A = 23; (b) 28, A = 64 (6 points)(Reference: Chang 2.17)a23 b) 11 Na 28 4Define, with two examples, the following terms: (a) alkali metals, (b) alkaline earth metal, (c) halogens, and (d) noble gases.(8 points)(Reference: Chang 2.22)aAlkali metals (1A): Lithium (Li); Sodium (Na)bAlkaline earth metal (2A): Magnesium (Mg); Calcium (Ca)cHalogen (7A): Fluorine (F); Chlorine (Cl)dNoble gases (8A): Helium (He); Neon (Ne)5Identify the following as elements or compounds: (a) NH3, (b) N2, (c) CO, (d) Co, and (e) He. (5 points)Elements: N2, Co, He.Compound: NH3, CO6
Z
=
64
Ni

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- Spring '15
- Khurana
- Chemistry, Atom, Chemical element, Inorganic Compounds