Exploring Atomic and Ionic Radius Trends

Dr. English discusses periodic table trends, focusing on atomic and ionic radii. The video explains how atomic radius decreases across a period due to increasing nuclear charge and increases down a group due to added electron shells. Ionic radius trends are also covered, showing how positive ions have smaller radii than their atoms, while negative ions have larger radii. The video concludes with practice questions to reinforce learning.

What is the atomic radius defined as?

• The total number of neutrons in the nucleus

• The distance from the nucleus to the outermost electron

• The number of protons in the nucleus

• The number of electrons in the outermost shell

As you move across a period from left to right, what happens to the atomic radius?

• It increases

• It decreases

• It remains the same

• It fluctuates randomly

Why does the atomic radius decrease across a period?

• Because the number of protons and electrons increases, causing a stronger attraction

• Because the atoms lose electrons

• Because the number of energy levels decreases

• Because the number of neutrons increases

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What is the trend of atomic radius as you move down a group?

• It increases

• It decreases

• It remains the same

• It fluctuates randomly

What happens to the ionic radius when an atom forms a positive ion?

• It fluctuates randomly

• It remains the same

• It becomes smaller

• It becomes larger

When an atom forms a negative ion, what happens to its ionic radius?

• It fluctuates randomly

• It remains the same

• It becomes smaller

• It becomes larger

How does the ionic radius trend compare between metals and nonmetals across a period?

• Metals increase, nonmetals decrease

• Both increase

• Metals decrease, nonmetals increase

• Both decrease

What is the general trend of ionic radius down a group?

• It decreases

• It fluctuates randomly

• It increases

• It remains the same

A magnesium atom differs from a magnesium ion in that the atom has a:

• Smaller nucleus

• Larger radius

• Larger nucleus

• Smaller radius

Within period 2 of the periodic table, as the atomic number increases, the atomic radius generally:

• Decreases

• Increases

• Follows no pattern

• Remains the same