20.
Atomic number is equivalent to its protons and electrons. :)
Whenever the motion of an object changes . . . speeding up, or slowing down,
or changing direction . . . that change is called "acceleration". Acceleration is produced by force on the object.If there is no force on the object, then there is no acceleration. That means that
its motion doesn't change. The object remains in constant, uniform motion .
moving with steady speed, in a straight line.
No force is necessary to keep an object moving, only to change its motion.
<span>These values also increase from the
bottom to the top of a group because the size of the atom decreases, resulting
in a smaller distance between the nucleus and the valence electron shell, which
increases the attraction between the protons and electrons.</span>
