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Material Type: Assignment; Class: General College Chemistry I; Subject: Chemistry (CHE); University: Monroe Community College; Term: Summer I 2009;
Typology: Assignments
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Practice Problems 4 Chapter 2 CHE 151 Graham/
1.) How many protons and neutrons are in the nuclei of 204 Tl atoms? __________
2.) What is the atomic number, mass number and symbol for the element that has 45 protons and 58 neutrons?
3.) Write the complete symbol for an atom with the following characteristics
a.) contains 19 electrons and 20 neutrons __________
b.) nitrogen atom with 8 neutrons __________
c.) bromine atom with a mass number of 80 __________
d.) mercury atom that contains 281 subatomic particles __________
e.) contains 20 protons and has a mass number of 42 __________
f.) cobalt atom with 33 neutrons __________
g.) iodine atom with 181 subatomic particles __________
h.) sulfur atom with 52 subatomic particles __________
i.) uranium atom with 146 neutrons __________
j.) copper atom with 65 nucleons __________
4.) Magnesium occurs in nature in three isotopic forms:
relative mass (^24) Mg (78.70% abundance) 23.985 amu
(^26) Mg (11.17% abundance) 25.983 amu
(^25) Mg (10.13% abundance) 24.986 amu
Calculate the atomic mass of Magnesium from these data
5.) Calculate the atomic mass of titanium on the basis of the following percent composition and isotopic mass data for the naturally occurring isotopes.
titanium-46 = 7.93% (45.95263 amu) titanium-47 = 7.28% (46.9518 amu) titanium-48 = 73.94% (47.94795 amu) titanium-49 = 5.51% (48.94787 amu) titanium-50 = 5.34% (49.9448 amu)
6.) Natural samples of copper contain two isotopes. 63 Cu has a mass of 62.930 amu and 65 Cu has a mass of 64.928 amu. The percent abundance of (^63) Cu is 69.09%. Calculate the atomic mass of copper.
7.) The two naturally occurring isotopes of chlorine are 35 Cl with a mass of 34.9689 amu and 37 Cl with a mass of 36.9659 amu. The atomic mass of elemental chlorine on earth is found to be 35.46 amu. Calculate the percent abundance of each of the two chlorine isotopes.
10.) How many electrons are in each of the following ions?
a.) Cu2+^ __________ b.) P3-^ __________
11.) What elements readily form cations? _____________________
12.) What elements readily form anions? _____________________
13.) Which members of group 14 (IVA) are classified as nonmetals?
14.) How much oxygen is required when 11.24 g of cadmium is converted to 12.84 g of cadmium oxide? ______________________
15.) The density of gold is 19.3 g/cm^3 , and the mass of a single gold atom is 3.27 x 10-22^ g. How many gold atoms are present in a piece of gold whose volume is 3.22 cm^3?