When we kick the ball, the force we apply to it causes it to accelerate from a speed of 0 to a speed of dozens of kilometers per hour. When the ball is released from the foot, it begins to decelerate (negative acceleration) due to the force of friction that is exerted upon it (as we observed in the previous example).
Elements are arranged according to their atomic number in increasing order.
When we move left to right we move along a period.The period in the periodic table tell us about the principal quantum number,(n).
When move from top to bottom we are moving in group. The group in the periodic tabletell us about the number of the valence electrons present in the valence shell of the elements of the particular group.
