Periodic Trends: Atomic Radius and Ionization Energy

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What is the trend in atomic radius across a period in the periodic table?

Atomic radius decreases across a period from left to right due to increasing nuclear charge.

Why does atomic radius decrease across a period?

As you move across a period, protons are added to the nucleus, increasing nuclear charge, which pulls electrons closer, decreasing atomic radius.

What is the trend in atomic radius down a group in the periodic table?

Atomic radius increases down a group due to the addition of electron shells.

Why does atomic radius increase down a group?

As you move down a group, additional electron shells are added, increasing the distance between the outer electrons and the nucleus.

What is ionization energy?

Ionization energy is the energy required to remove an electron from an atom in the gaseous state.

What is the trend in ionization energy across a period?

Ionization energy increases across a period from left to right.

Why does ionization energy increase across a period?

This is due to increasing nuclear charge, which holds electrons more tightly, requiring more energy to remove an electron.

What is the trend in ionization energy down a group?

Ionization energy decreases down a group.

Why does ionization energy decrease down a group?

Despite the increasing nuclear charge, the added electron shells reduce the effective nuclear attraction, making electrons easier to remove.

How do atomic radius and ionization energy compare across a period?

As atomic radius decreases, ionization energy increases across a period.

How does a greater atomic radius affect ionization energy?

A greater atomic radius often leads to lower ionization energy because outer electrons are further from the nucleus.

What is electron shielding?

Electron shielding is the phenomenon where inner electrons block attraction between the nucleus and outer electrons.

How does electron shielding affect periodic trends?

It causes the effective nuclear charge felt by outer electrons to decrease, influencing trends such as atomic radius and ionization energy.

What is effective nuclear charge?

Effective nuclear charge is the net positive charge experienced by an electron in an atom, influenced by shielding.

How is effective nuclear charge related to periodic trends?

Higher effective nuclear charge leads to a decrease in atomic radius and an increase in ionization energy across a period.