Question

1 multiple choice 1 point
atomic radii increases in a period from ____ to ____.
○ top; bottom
○ right; left
○ left; right
○ bottom; top

2 true or false 1 point
f⁻¹ is smaller than its neutral atom, f.
○ true
○ false

3 true or false 1 point
nonbonding radius is the shortest length separating the nuclei of two atoms during a collision.
○ true
○ false

Explanation:

Question 1

To determine the direction of atomic radius increase in a period, we recall the periodic trend: in a period (horizontal row), as we move from right to left, the atomic radius increases. This is because the effective nuclear charge increases from left to right, pulling electrons closer, so radius decreases. So the correct option is the one with "right; left".

When a fluorine atom (F) gains an electron to form \( F^- \) (note: the charge is -1, often written as \( F^- \) not \( F^{-1} \)), the added electron increases electron - electron repulsion. The electron cloud expands, so the ionic radius of \( F^- \) is larger than the atomic radius of F. So the statement " \( F^{-1} \) is smaller than its neutral atom, F" is false.

The non - bonding radius (also called van der Waals radius) is the distance between the nuclei of two non - bonded atoms in close contact. The shortest length separating the nuclei of two atoms during a collision is related to the bonding radius (covalent radius for bonded atoms or the distance in a collision which is different from non - bonding radius concept). So the statement "Nonbonding radius is the shortest length separating the nuclei of two atoms during a collision" is false.

Answer:

B. right; left (assuming the options are labeled as A. top; bottom, B. right; left, C. left; right, D. bottom; top)

Question 2