The quantum mechanical model is used to describe the energy and most likely location of an electron.
Answer: Option A
<u>Explanation:
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The quantum mechanical model leads to the introduction of quantum numbers representing the energy levels, sub-shells, orbitals as well as spin states of the electrons. So according to the quantum numbers we can perfectly define the position and energy of any electron in an element.
According to Pauli’s principle, any two electron cannot be having same set of quantum numbers. So, using the principle quantum number, azimuthal quantum number, magnetic and spin quantum number, we can define the energy and location of an electron in the atom.
Answer:
d. A water particle and an air particle
Explanation:
The force of gravity (F) between two objects of masses m1 and m2 and separated by a distance r is given as:

where G is the gravitational constant
This force is therefore, directly proportional to the masses and inversely related to the distance between them.
Based on the given options, since the masses of the water and air particles are very small (masses of earth, moon and sun is relatively huge), the gravitational force between them would be negligible and difficult to measure.
Answer:
C
Explanation:
Think about it. If you accelerate, you go faster. This means you change speed.