Periodic Trends in Chemistry

What happens to atomic radii as you move from left to right across the periodic table?

Ionic radii increase from bottom to top in a group.

What is the term used to describe the phenomenon where inner electrons shield outer electrons from the nucleus's attraction?

The energy needed to remove an electron from a neutral gaseous atom is called __________.

Match the following elements with their ionization energy characteristics:

Which of the following statements is true regarding first ionization energy?

Cations are formed when an atom gains electrons.

In a group of elements, atomic radii __________ as you move down the group.

Periodic Trends

The periodic table organizes elements based on electron configurations, revealing patterns known as periodic trends.
Atomic and ionic radii are influenced by factors like effective nuclear charge and electron shielding.

Atomic Radii Trends

Atomic radii decrease across a period (left to right) due to increasing nuclear charge and the reduced shielding effect.
Atomic radii increase down a group due to the increasing number of electron energy levels.

Ionic Radii Trends

Metal cation radii are smaller than their neutral atom counterparts, as valence electrons are lost.
Non-metal anion radii are larger than their neutral atom counterparts, as extra electrons increase electron-electron repulsion.

Explanations of Trends

Trend 1 (across periods): Effective nuclear charge increases, pulling electrons closer to the nucleus, leading to smaller atomic and ionic radii.
Trend 2 (down groups): Presence of increasing electron shells; more electron shielding occurs, hence wider spaced orbitals, resultant larger volumes .

Ionization Energy

Ionization energy is the energy needed to remove an electron from a gaseous atom.
Ionization energy increases across a period because the effective nuclear charge increases, making it harder to remove an electron.
Ionization energy decreases down a group, since increasing electron shielding makes it easier to remove an electron.

Explore the fascinating world of periodic trends in the periodic table. This quiz examines the behavior of atomic and ionic radii, revealing how electron configurations influence these properties. Test your understanding of trends across periods and groups.