Trends in Atomic and Ionic Sizes

The video tutorial explains the trends in atomic and ionic radii across the periodic table. It discusses how atomic size decreases across a period due to increased effective nuclear charge and increases down a group due to additional energy levels. The video also compares the sizes of atoms and ions, highlighting that cations are smaller than their parent atoms, while anions are larger due to electron repulsion. The tutorial concludes with a discussion on ionic radii trends, noting that ionic size decreases across a period and increases down a group.

What happens to the atomic size as you move from left to right across a period in the periodic table?

• It fluctuates randomly.

• It remains the same.

• It decreases.

• It increases.

Why does the atomic size decrease as you move across a period?

• Increase in the number of core electrons.

• Decrease in the number of protons.

• Increase in effective nuclear charge.

• Decrease in energy levels.

Which element is larger: sodium or lithium, and why?

• Sodium, because it has more energy levels.

• Lithium, because it has fewer protons.

• Sodium, because it has fewer protons.

• Lithium, because it has more energy levels.

What is the effective nuclear charge experienced by the valence electron in a sodium atom?

• +2

• +9

• +1

• +11

How does the size of a cation compare to its parent atom?

• Cations have no definite size.

• Cations are the same size.

• Cations are smaller.

• Cations are larger.

Why are anions generally larger than their parent atoms?

• They have more protons.

• They have a higher effective nuclear charge.

• They have more electrons causing repulsion.

• They have fewer energy levels.

What happens to the ionic radii as you move down a group in the periodic table?

• It remains constant.

• It increases.

• It fluctuates.

• It decreases.

How does the ionic radii trend compare to the atomic radii trend?

• Ionic radii are always larger.

• They follow opposite trends.

• Atomic radii are always larger.

• They follow the same trend.

What is the effect of crossing from cations to anions on ionic size?

• Size decreases.

• Size increases.

• Size remains the same.

• Size fluctuates.

Which ion is generally larger: phosphide or fluoride, and why?

• Phosphide, due to electron repulsion.

• Fluoride, due to more protons.

• Fluoride, due to fewer electrons.

• Phosphide, due to more energy levels.