Periodic Table Trends and Electron Affinity (English)

Vocabulary flashcards covering key periodic table concepts from the notes.

Periodic table

A chart organizing elements by increasing atomic number to reveal patterns in properties across periods and groups.

Ionization energy

Energy required to remove the outermost electron from a neutral atom; increases across a period and decreases down a group.

Shielding (screening) effect

Reduction in the effective nuclear charge felt by outer electrons due to inner electrons shielding the nucleus.

Effective nuclear charge (Z_eff)

Net positive charge experienced by valence electrons after shielding; increases across a period, contributing to higher ionization energy.

Atomic radius

Size of an atom; generally decreases across a period and increases down a group.

Electron affinity

Energy change when an electron is added to a neutral atom; becomes more negative across a period; halogens have high electron affinity.

Halogen

Group 17 elements with high electron affinity and high reactivity; seek one electron to complete their valence shell.

Alkali metal

Group 1 elements that readily lose one electron to form +1 ions; have low first ionization energy.

Noble gas

Group 18 elements with full valence shells and very low reactivity.

Valence electron

An outermost electron involved in bonding and determining chemical properties.

Proton

Positively charged subatomic particle in the nucleus; contributes to atomic number and nuclear charge.

Electron

Negatively charged subatomic particle in electron shells; participates in bonding and determines ionization behavior.

Period

Horizontal row in the periodic table; properties change gradually across the row.

Group

Vertical column in the periodic table; elements in a group share similar chemical properties.

Energy levels

Electron shells around the nucleus where electrons reside; higher levels are farther from the nucleus.