Download CH115 SI Summer 2014 Ch. 2 (Part B): Kelly Texter Atoms

CH115 SI Summer 2014
Kelly Texter
Ch. 2 (Part B):
Atoms & Elements
Isotopic Mass= (# protons in isotope)(1.00728amu) + (# neutrons in isotope)(1.00866amu)
Atomic Weight= [(fractional abundance A)(isotopic mass A) + (fractional abundance B)(isotopic mass B)]
1. Changing the number of neutrons in an atom affects its _______?
a. Charge
b. Mass
c. Volume
2. Changing the number of electrons in an atom causes the greatest change in an atom’s ______?
a. Charge
b. Mass
c. Volume
3. Write the symbol of the isotope (or isotopic ion) what you get when you
Remove 44 protons, 74 neutrons, and 43
electrons from 197Au
Remove 6 protons, 10 neutrons, and 4
electrons from 56Fe2+
Add 28 protons, 38 neutrons, and 26
electrons to 19F-
4. Given the following relative abundances, calculate the atomic weight of silicon.
28
Si= 92.23%, 29P= 4.67%, 30P= 3.1%
5. If the four isotopes for Sulfur (Sulfur-32, Sulfur-33, Sulfur-34, Sulfur-36) have percent abundances
of 95.02%, 0.75%, 4.21%, and .02% respectively, calculate the atomic weights of sulfur.
First Exam on _____________!!!!!
CH115 SI Summer 2014
Kelly Texter
Ch. 2 (Part B):
Atoms & Elements
6. Calculate the isotopic mass of a 59Co atom.
7. A sample of 21.56 g of Li is found to contain only 6Li and 7Li. If 19.95 g of the sample is 7Li, what
are the percent abundances of 6Li and 7Li in the sample?
8. Perfluorodecalin (C10F18) is a liquid that is used as part of an FDA-approved artificial blood during
certain surgeries. The density of perfluorodecalin is 1.908 g/mL. How many moles of
perfluorodecalin are there in 4.750 L of this molecular compound?
9. How many atoms of oxygen are found in 13.9 mol of acetic acid (C2H4O2)?
(*Hint* Oxygen is a diatomic gas)
10. What charges do the elements in the following groups achieve when they ionize?
Halogen _____
Alkali Earth Metals _____
Boron group _____
Alkali Metals _____
Chalcogens _____
First Exam on _____________!!!!!