PLEASE HELP!! Determine the Z and A number for an atom with 20 protons, 19 neutrons and 18 electrons. What element would this be in the periodic table? Write the symbol for this atom with the Z and A numbers accordingly. Is this an atom or an ion? If an ion, what is the charge on it?

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative