Europium is used to make the phosphors in TV screens. How many protons, neutrons
ID: 531681 • Letter: E
Question
Europium is used to make the phosphors in TV screens. How many protons, neutrons, and electrons are in an atom of^153 _63 Eu^3+ ? Classify this element with a designation, name, or term we have associated with different regions of the periodic table. Reduce the following expression to a dimensionless number, taking care to preserve the correct number of significant digits. Note that the relationship between centimeters and inches is expressed EXACTLY as 2.54 cm = 1 in. (7.30258 in - 7.30233 in) 4289.0cm/12.0005 km^2 How deep in meters is 20,000 leagues under the sea? (Report your answer with 5 significant digits) (1 league = 24 furlongs, 1 mile = 8 furlongs, 1 foot = 1.8939 times 10^-4 miles, 1 inch = 2.54 cm)Explanation / Answer
Q 1) Europium has 63 protons, 63 electrons and 89 neutrons.
It appears in the 6th period of periodic table and an f block element. It is placed under the group Lanthanides. It is commonly refered to as Lanthanide element.
Q 3) 1 league = 24 furlongs
thus 20,000 leagues = 20,000*24 = 480000 furlongs
8 furlongs = 1 mile
hence 480000 furlongs = 480000/8 = 60000 miles
1.8939*10-4 miles = 1 foot
thus 60000 miles = 60000/1.8939*10-4 = 316806589.577 feet
1 foot = 12 inches
hence 316806589.577 feet = 316806589.577*12 = 3801679074.92 inches
1 inch = 2.54 cm
thus 3801679074.92 inches = 3801679074.92*2.54 = 9656264850.31 cm
1 meter = 100 cm
Hence 9656264850.31 cm = 96562648.5031 meter = 9.6562*105 meters
Therefore, 20,000 leagues = 9.6562*105 meters
Q 2) (7.30258in - 7.30233in)4289.0cm = 0.000249999in*4289.0 cm = 0.000634999*4289.0 cm = 2.7235 cm2
12.005 Km2 = 12.005*1010 cm2 Since, 1 Km = 100000 cm
Thus, 2.7235/12.005*1010 = 0.22686*10-10 (no dimensions)
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