Tp Which important step should you take before you design your experiment, to find out if someone else has asked the same question before, and to get more information?
O A. Test
OB. Research
O C. Hypothesize
OD. Observe

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.