Chem electronegativity and stuff

Ionization Energy

Energy required to remove an electron from a gaseous atom.

Atomic radius

Half the distance between nuclei of identical bonded atoms.

Electronegativity

An atom’s ability to attract bonding electrons.

Valence electrons

Electrons in the outermost shell available for bonding.

Cation

Positive ion formed by losing electrons.

Anion

Negative ion formed by gaining electrons.

Effective nuclear charge

More protons = stronger pull on electrons.

Shielding effect

Inner electrons block nuclear pull on valence electrons.

Distance from nucleus

More shells = electrons farther from nucleus.

Atomic radius across a period

Decreases — more protons pull electrons inward.

Atomic radius down a group

Increases — more energy levels.

Ionization energy across a period

Increases — electrons held tighter.

Ionization energy down a group

Decreases — electrons farther from nucleus.

Electronegativity across a period

Increases — stronger pull on bonding electrons.

Electronegativity down a group

Decreases — weaker pull.

Why is K⁺ smaller than K?

Loses an energy level; remaining electrons pulled closer.

Why high IE = high EN?

Strong nuclear attraction both holds electrons tightly and attracts bonding electrons.

Cations vs anions size

Cations shrink; anions expand.

More protons →

Smaller atom, higher IE, higher EN.

More shells →

Bigger atom, lower IE, lower EN.