Marie can determine which boxes contain the most reactive elements by using information about their locations on the periodic table, specifically:
- Group Number (Vertical Column): Elements in Group 1 (alkali metals) and Group 17 (halogens) are known to be highly reactive. Alkali metals have one valence electron and readily lose it, making them very reactive metals. Halogens have seven valence electrons and are highly reactive nonmetals because they readily gain an electron
- Number of Valence Electrons: Elements with one valence electron (like alkali metals) or seven valence electrons (like halogens) tend to be more reactive. This is because they are eager to lose or gain electrons to achieve a stable electron configuration
- Position in the Group (Period): Reactivity trends vary down a group. For alkali metals, reactivity increases as you go down the group because the outer electron is farther from the nucleus and more easily lost. For halogens, reactivity decreases down the group because the atoms get larger and less able to attract electrons
- Metal vs. Non-Metal: Alkali metals are the most reactive metals, with cesium and francium being among the most reactive, though francium is rare and radioactive. Fluorine is the most reactive nonmetal among halogens
Thus, by examining the group number, valence electron count, and period number of the elements indicated on the boxes, Marie can identify those containing the most reactive elements-typically alkali metals in Group 1 and halogens in Group 17, especially those lower in the group for metals and higher in the group for nonmetals
