Atomic Radius and Ionic Radius Concepts

The video explores periodic trends in atomic and ionic radii. It defines atomic radius as half the distance between two bonded nuclei and explains why it's challenging to measure directly. The video discusses how atomic radius changes across periods and down groups, influenced by effective nuclear charge and shielding. It also covers ionic radius, noting that cations are smaller and anions are larger than their parent atoms due to electron-proton interactions and electron repulsion.

What is the atomic radius formally defined as?

• Half the distance between two bonded nuclei

• The distance from the nucleus to the outermost electron

• The diameter of an atom

• The distance from the nucleus to the edge of the electron cloud

How does atomic radius change across a period from left to right?

• It increases

• It remains constant

• It decreases

• It fluctuates

What is the effect of shielding in an atom?

• It increases the size of the nucleus

• It increases the nuclear charge experienced by valence electrons

• It reduces the nuclear charge experienced by valence electrons

• It has no effect on nuclear charge

How is effective nuclear charge calculated approximately?

• Atomic number minus the number of inner electrons

• Number of inner electrons plus atomic number

• Atomic number plus the number of inner electrons

• Number of valence electrons minus atomic number

Why does atomic radius increase down a group?

• Due to increasing nuclear charge

• Because of decreasing energy levels

• Because valence electrons enter new energy levels further from the nucleus

• Due to decreasing shielding effect

What happens to the atomic radius as effective nuclear charge increases across a period?

• It increases

• It decreases

• It remains the same

• It fluctuates

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

• It is smaller

• It is larger

• It is the same size

• It varies depending on the element

What is the reason for anions being larger than their parent atoms?

• Increased nuclear charge

• Loss of electrons

• Greater electron repulsion due to extra electrons

• Decreased electron repulsion

Which of the following has a larger ionic radius: sodium or sodium ion?

• Both are the same

• Sodium ion

• Sodium

• It depends on the environment

What is the ionic radius of a chloride ion compared to a chlorine atom?

• It depends on the charge

• The same

• Larger

• Smaller