D
The exact location of electrons in electron shells of atoms cannot be exactly ascertained. This is why VSPER atomic models represent the position of electrons (s, p, d, & f) using the probability of where they would most be expected to be found.
Explanation:
This is because merely observing electrons changes their behavior. Remember that to observe something one has to shine light on it so it bounces back to the eye. Due to the negligible mass of electrons, mere photons of light will change their direction of movement, spin or other behaviors/properties.
Learn More:
For more on electron clouds check out;
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Acceleration means speeding up, slowing down, or changing direction. The graph doesn't show anything about direction, so we just have to examine it for speeding up or slowing down ... any change of speed.
The y-axis of this graph IS speed. So the height of a point on the line is speed. If the line is going up or down, then speed is changing.
Sections a, c, and d are all going up or down. Section b is the only one where speed is not changing. So we can't be sure about b, because we don't know if the track may be curving ... the graph can't tell us that. But a, c, and d are DEFINITELY showing acceleration.
Answer:
The average atomic mass is 79.91 amu.
Explanation:
Since
Atomic mass can be find by Multiplying the relative abundance of each isotope by its atomic mass, then add them together to get the atomic mass of the element.
so
Atomic mass = (0.5069)(78.92 amu) + (0.4931)(80.92 amu)
=79.91 amu
So the Atomic mass of the bromine is 79.91amu.
If you're listening to a sound that has a steady pitch, and suddenly the
pitch goes up, then you know that two things could have happened:
EITHER ...
-- The person or other source making the sound could have
raised the pitch of the sound being produced.
OR ...
-- The person or other source making the sound could have
started moving toward you.
OR ...
-- both.
Even if the pitch of the sound leaving the source doesn't change,
you would still hear it increase if the source starts moving toward
you. That's the so-called "Doppler effect".