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Structure of a Atom

Question 1
The diameter of a neutral helium atom is about 168 pm. Suppose we could lin up helium atoms side by side in contact with one another. Approximately how many atoms would it take to make the distance 1 cm from end to end. Round to the nearest whole number, do not include units or commas. do not use scientific notation.

Question 2
What is the symbol for the element that has 28 protons?

Question 3
How many neutrons are in an element of 243Pu?

Question 4
How many protons are in an atom of carbon-14?

Question 5
The number of protons, neutrons and electrons, respectively, in 115Cd2+ are
48, 46, and 67
48, 67, and 46
46, 67, and 48
46, 115, and 67

Question 6
What is the name of Al(OH)3?

Question 7
What is the name of the following compound?
C2O4

Question 8
What is the name of the following compound?
CaCl2

Question 9
Write formulas for the following. use the format CO2 for CO2 and H2O for H2O. Use parentheses only when necessary.
lithium hydroxide
sodium carbonate
nickel (II) sulfide
dinitrogen tetraoxide
copper (I) sulfate

Question 10
Which of the following is most likely to form an anion with a charge of -2?
sodium
calcium
magnesium
oxygen
more than one will carry that charge

Question 11
If shown the formula, give the name (do not capitalize), if shown the name, give the formula (use parentheses only when necessary, capitalize as necessary, use the format CO2 for CO2). If a compound can be written as more than one way, we will be using the format that is used in your text.
NiSO4
Al2O3
silver chloride
ammonium acetate
CO

Question 12
Which of the following are incorrectly matched? More than one may be chosen.
Answer
MgCO3 magnesium carbonate
NiNO3 Nickel (II) nitrate
Ca(NO3)2 calcium dinitrate
(NH4)2SO4 ammonium sulfate
Cu(OH)2 copper hydroxide

Question 13
What is the average atomic mass of silver according to the following data? Use four decimal places, do not include units.
isotope name isotope mass percentage
Silver-107 107.19119 51.86
Silver 109 109.36254 remainder

Question 14
Fill in the following table: Assume element is neutral unless otherwise indicated.
Symbol protons neutrons electrons net charge

Question 15
How many electrons are in an atom of O2-?

Question 16
Which of the following is most likely to form an ion with a +1 charge? more than one may be chosen
Li
Br
K
O
Question 17
A quarter is 2.5 cm in diameter. How many dollars worth quarters would have to be lined up in a row to reach a length of 1 meter?

Question 18
How many cars are there in a long freight train if it take the entire train 2 minutes to pass a station as it travels at 40 miles/hour? Each car is 50 feet long. Round to the nearest whole number, do not include units in your answer.

Question 19
The price of a ream of paper is $3.30. There are 500 sheets of paper in a ream. If a sheet of paper weighs 0.500 oz, what is the price of a kg of paper?
What is the cost of one sheet of paper?
What is the mass (grams) of one sheet of paper?

Question 20
The average atomic mass of Cu is 63.55 and is found in two naturally occurring isotopes. 63Cu has an atomic mass of 62.93 and 65Cu has an atomic mass of 64.94. What is the percentage of 63Cu in the sample? Round to one decimal place, do not include units in your answer.

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