Enter the number of each atom to balance the following equation

P4=1 , Br2=6, PBr3=4

Explanation: You would have 4 P's and 12 Br's on both sides. The equation is now balanced.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

that tool would be a compass