A highway engineer is researching de-icing compounds for clearing ice from streets in winter. She wants a compound that has +2 ions and -1 ions in it.

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.

може ли да зареждате повече информация, моля