Atomic Models
Many models of molecules represent individual atoms as solid balls. What is this type of atomic model called?
Billiard ball model / Dalton's model
What 2 subatomic particles are in the nucleus?
Protons and neutrons
An atom has 8 protons, 9 neutrons, and 10 electrons. What is its atomic number?
8
All isotopes of the same element have the same number of ___________.
Protons
alpha, beta, gamma
How are Rutherford's nuclear model and Bohr's model different?
Bohr's model shows different energy levels for electrons, while the nuclear model doesn't
How is the electron cloud held to the nucleus?
Electrostatic attraction / attraction between positive nucleus and negative electrons
Halogens are what group number?
17
Neutrons
Name at least one way nuclear reactions are used.
Nuclear power plants (atomic bombs, but I wouldn't call them "useful"), nuclear chemistry, carbon-dating
What subatomic particle did JJ Thomson discover with his cathode-ray tube experiments? And what model did he develop as a result?
The electron
The plum-pudding model
An atom has 12 electrons. How many are in each energy level?
2 - 8 - 2
What do elements in the same group have in common?
Same number of valence electrons
Which has more neutrons - C-14 or N-14?
C-14
Uranium-238 undergoes alpha decay. What are the two products?
Thorium-234 and an alpha particle (2 protons and 2 neutrons, or He-4)
Draw a Bohr model of carbon-12
6 protons and 6 neutrons in the nucleus, 6 electrons, with 2 in the 1st level and 4 in the second level
How are O2- and Ne similar? How are they different?
Similar: same number of electrons
Different: numbers of protons and neutrons
An element has the same number of valence electrons as sodium (Na) and the same number of energy levels as antimony (Sb). What is it?
Rubidium (Rb)
Germanium has two major isotopes - 73Ge and 74Ge. Which is more abundant? How do you know?
73Ge - because the average atomic mass for germanium on the periodic table is closer to 73 than 74.
When the universe first formed, there was only hydrogen. How did we get all the other elements that exist today?
Nucleosynthesis / nuclear fusion in stars and supernovas
What is inaccurate about Bohr's model?
Electrons do not actually orbit the nucleus as individual particles in neat paths; they are actually waves and particles at the same time and we can only predict where they are likely to be (electron cloud)
The protons in the nucleus repel each other because they are all positive. What keeps the nucleus from flying apart?
The strong nuclear force
An element is completely unreactive to other elements and has 4 electron energy levels. What is it?
Krypton (Kr) [unreactive -> noble gas -> group 18!]
Ruthenium (Ru) has 3 common isotopes. How many neutrons does the most common isotope have?
57 (atomic mass rounds to 101, 101 - 44 = 57)
In nuclear power plants, fission of U-235 is triggered by a neutron. If one of the products of the collision between a neutron and U-235 is Ba-141 AND 3 additional neutrons are released, what is the other product?
Kr-92
[(235/92) U + (1/0)n -> (141/56)Ba + 3 (1/0)n + (92/36) Kr]