12. Which of the following statements about electrons refer to the Bohr Model of an atom?
A. move at a very high velocity around the nucleus
B. exist at different energy levels in orbit around the nucleus
C. can move between energy levels when they gain or lose energy
D. all of the above

13.
The following are rules/principles used in arranging the electrons around the
nucleus of an atom EXCEPT
A. Hund's Rule
B. Aufbau Principle
C. Pauli Exclusion Principle
D. Heisenberg's Uncertainty Principle

14. If a neutral atom has 18 electrons, what is the highest principal energy level
that its outermost electrons will occupy?
A. 1
B. 2.
C.3
D. 4​

There is a theory that indicates that dinosaurs became extinct when about 65 million years ago, a large asteroid hit the earth surface. dust caused by this collision blocked the sunlight reaching the earth's surface and many forms of life became extinct due to the cold. fearing this threat, how large the radius of an asteroid should you be looking for if the dangerous asteroid size is approximately the same as the one that killed the dinosaurs? available data suggests that about 18% of that asteroid's mass ended up as a dust spread evenly over earth after eventually settling out of the upper atmosphere. about 0.0180 g/cm^2 of dust, which is chemically different than the earth's rock, covered the earth's surface. typical asteroids have a density of about 1.9 g/cm^3. now that we know the size of the asteroid, how much energy was released during impact, assuming all of it was just the kinetic energy of the asteroid right before the impact?

How many molecules are present in 3 mols of silicon dioxide (sio2)?

Why should seat belts not be mandatory quick plz