Why do elements in the same group or column of the periodic table have similar properties?

a.
they have the same number of protons.

b.
they have the same number of electron shells.

c.
they have the same number of outer shell electrons.

d.
they have the same number of neutrons.

The graph describes the motion of an object. the object moves with from a to b. it from b to c. it moves with from c to d.

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?