Question

In each pair, choose the atom which is larger based on its periodic trend.

1. Sb or Bi
2. Sr or Te
3. Cr or Cr³⁺
4. Se²⁻ or Te²⁻

Answer 1

The larger atoms in each pair are Bi, Sr, Cr, and Te²⁻ based on their positions on the periodic table and the effect of electron shells and charges on atomic radii.

Step-by-step explanation:

Periodic trends in the periodic table allow us to predict the relative sizes of atoms and ions:

1. Bi is larger than Sb because it is located further down the same group in the periodic table, leading to a larger atomic radius due to additional electron shells.
2. Sr is larger than Te as it is located to the left and below in the periodic table, which means it has more electron shells and thus a larger atomic radius.
3. Cr is larger than Cr³⁺. When an atom loses electrons and forms a cation, the loss of electron repulsion and increased nuclear charge causes the atomic radius to decrease.
4. Se²⁻ is smaller than Te²⁻. As you go down the group in the periodic table, ions with the same charge have an increasing number of electron shells, resulting in larger size.