Question

Which atom or ion is the largest?

A. K
B. K+
C. Ca
D. Ca2+
E. Li

Answer 1

A. K

Step-by-step explanation:

The largest atoms are in the lower left corner of the Periodic Table.

Answer 2

A. K

Step-by-step explanation:

Remember the trends in the Periodic Table:

• Atomic radii decrease from left to right across a Period.
• Atomic radii increase from top to bottom in a Group.
• Ionic radii of metal cations are smaller than those of their atoms.

Thus, the largest atoms are in the lower left corner of the Periodic Table.

The diagram below shows that K is closest to the lower left, so it is the largest atom. It is also larger than any of the cations.