Which of these substances is an example of a solution? oil and vinegar dressing
brass
mercury
concrete

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.

idk what is it? is this a question that you know the answer or u dont

answeridentity;