Question

as we move across the periodic table of elements, certain trends are evident. the placement of individual elements in the periodic table allows us to predict many characteristics of elements such as state of matter at room temperature, reactivity, and valence electrons just to name a few. as one moves from left to right across the periodic table, what two trends are evident? a atomic radius increases moving left to right. b nonmetallic character increases moving left to right. c electron affinity increases across the periodic table. d elements change from solids to liquids and then gases. e most reactive elements on left and least reactive on right.

Explanation:

• Option A: Atomic radius decreases left to right as protons pull electrons closer, so this is incorrect.
• Option B: Nonmetallic character increases left to right because elements gain electrons more easily, which is a valid trend.
• Option C: Electron affinity generally increases left to right (with minor exceptions), which is a valid trend.
• Option D: Elements do not follow a strict solid→liquid→gas pattern across a period; many remain solid, so this is incorrect.
• Option E: Reactivity varies: metals on the left are reactive, but nonmetals on the right (like halogens) are also highly reactive, so this is incorrect.

Answer:

B. Nonmetallic character increases moving left to right.
C. Electron affinity increases across the periodic table.