Waves can transfer energy, but they... 1-always have the same wavelength

2-cannot carry sound

3-are unable to move through empty space

4-do not move matter

A.

Explanation:

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.

just did the assignment and the answer was #1 +2 n