Ionic Radii and Their Trends

The video tutorial explains the concept of ionic radius, detailing the differences between cations and anions. It describes how the ionic radius changes when an atom loses or gains electrons, affecting the size of the ion. The tutorial also covers periodic trends, showing how ionic radii vary across periods and down groups in the periodic table. Key examples include sodium and fluorine ions, illustrating the changes in ionic size due to electron loss or gain.

What is the ionic radius?

• The distance between the nucleus and the outermost electron shell of an atom

• The distance between the nucleus and the innermost electron shell of an ion

• The distance between the nucleus and the outermost electron shell of an ion

• The distance between two ions in a compound

Which of the following is a cation?

• Sodium ion

• Chlorine ion

• Oxygen ion

• Fluorine ion

Why is the radius of a cation smaller than its parent atom?

• Because it gains electrons

• Because it loses protons

• Because it loses electrons and the remaining electrons are pulled closer to the nucleus

• Because it gains protons

What happens to the size of a sodium atom when it becomes a sodium ion?

• It remains the same

• It decreases

• It fluctuates

• It increases

Why is the radius of an anion larger than its parent atom?

• Because it loses electrons

• Because it gains protons

• Because it gains electrons and the added electrons repel each other, increasing the size

• Because it loses protons

What is the effect of adding an electron to a fluorine atom?

• The size decreases

• The size increases

• The size remains the same

• The size fluctuates

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

• They increase

• They decrease

• They fluctuate

• They remain constant

Why do ionic radii increase down a group?

• Because the atomic mass decreases

• Because the number of protons increases

• Because the number of electron shells increases, causing more shielding

• Because the number of neutrons increases

What happens to ionic radii as you move across a period in the periodic table?

• They increase

• They fluctuate

• They remain constant

• They decrease

Why do ionic radii decrease across a period?

• Because the atomic mass increases

• Because the number of electron shells increases

• Because the number of protons increases, pulling electrons closer

• Because the atomic number decreases