Atomic Structure
What are the three(3) components that make up an atom?
Protons, Electrons, Neutrons
An isotope is an atom with a different number of _____.
A.Protons
B.Neutrons
C. Electrons
D. Both A & C
B. Neutrons
What is a half-life?
A. The amount of mass of a radioactive isotope that decays over time.
B. The amount of time it takes for 1/2 the mass of a radioactive isotope to decay.
B. The amount of time it takes for 1/2 of a radioactive isotope to decay.
What are the four types of nuclear radiation?
α - Alpha Particles
β+ - Beta Positive Decay
β- - Beta Minus Decay
γ - Gamma Radiation
Which has a neutral charge?
Protons or Neutrons
Neutrons
[NOTE: Protons have a positive charge]
Which 2 subatomic particles make up the nucleus of an atom and make up most of atoms mass?
Protons & Neutrons
How many protons, electrons and neutrons does the isotope 26Mg contain?
[Note: Atomic # of Mg is 12]
Protons: 12
Electrons: 12
Neutrons: 14
If the half life of a substance is 25 years, how many half-lives would have occurred after decaying for 125 years.
5 years
(Two time variables given, # of Half-Lives Occurred = 125y / 25y)
Which type of nuclear radiation can be blocked by a piece of paper or skin?
A. Alpha (α)
B. Beta (β)
C. Gamma (γ)
D. Neutrons (n)
A. Alpha Particles (α)
Which of these radiations has the fastest speed of travel?
Alpha or Gamma
Gamma
[Note: Alpha radiation is the slowest]
If the element Rubidium (Rb) contains 37 protons in it's nucleus. How many electrons does this atom contain?
37 electrons
[Note: For atoms, the number of protons and electrons are usually equal to each other.]
Which isotope is more abundant Copper-63 or Copper-65 if Copper has an average atomic mass of 63.55 amu?
Copper-63
If a substance begins with an original mass of 600 grams, how many half lives would have occurred for it to reduce to 9.375 grams?
6 Half-Lives
(Since two mass variables are given, we would divide 600 grams by 2 until we get to 9.375 grams.)
[600 > 300 > 150 > 75 > 37.5 > 18.75 > 9.375]
What particle is released from Beta-Minus Decay?
A. 01e
B. 42He
C. 0-1e
D. 00 γ
C. 0-1e
Which type of radiation is defined by photons traveling in a wave-like pattern at the speed of light?
Electromagnetic Radiation or Ionization/Particle Radiation
Electromagnetic Radiation
[Note: With ionization/particle radiation, instead of light, these are fast moving subatomic particles.]
What type of charge do electrons have? Where is it located in an atom?
Electrons have a negative charge and are found orbiting around the nucleus.
Carbon-12 makes up 99.45% of all of the carbon atoms (C-12 = 99.45%), while carbon-14 makes up the remaining 0.55% (C-14 = 0.55%). Calculate the average atomic mass of carbon?
12.011 amu
Neptunium-240 has a half-life of 1 hour. After 4 hours, 3.75 grams of Np-240 remain. How many grams were in the original sample of Np-240?
60 g
What is the missing variable?
2312Pt-> 2311Na+ ____ +v
01e (Beta-Positive)
When a large atom splits into 2 or more smaller ones, this is known as?
Fission or Fusion
Fission
[Note: Fusion is when 2 or more lighter atoms join together make a larger atom.]
If the element Lead (Pb) has an atomic number of 82 and an atomic mass of 207 amu. How many neutrons does it contain?
207-82 = 125 Neutrons
The three silicon isotopes have atomic masses and relative abundances of 27.98 amu (92.23%), 28.98 amu (4.68%) and 29.97 amu (3.09%). Calculate the atomic mass of silicon.
28.09 amu
If 100 grams of Au-198 decays to 6.25 grams in 10.8 days, what is the half-life of Au-198?
2.7 Days
What is the missing variable?
____ -> 23490Th + 42He
[Note: 87Fr , 88Ra, 89Ac, 90Th, 91Pa, 92U, 93Np]
23892U
Band of Stability: Which has a stability ratio of P1+:N10?
Light Elements or Heavy Elements
Light Elements
[Note: Heavy Elements have a stability ratio of P1+:N1.50]