Periodicity

Why does CA (Coulombic Attraction) increase going across the periodic table?

Because the number of protons in the nucleus increases, leading to a stronger positive charge that pulls electrons closer to the nucleus.

Why does CA decrease going down the periodic table?

As you move down a group, electrons are added to higher energy levels, increasing distance from the nucleus and resulting in weaker attraction.

Why does ionization energy (IE) increase across a period?

Because the number of protons increases, resulting in stronger attraction between the nucleus and outermost electrons, making it harder to remove an electron.

Why does IE decrease going down a column?

As atomic radius (AR) increases down a group, valence electrons are further from the nucleus, experiencing less attraction and are easier to remove.

Why does AR decrease going across a row?

The number of protons increases, resulting in a stronger positive charge that pulls electrons closer, effectively shrinking the atomic size.

Why does AR increase going down a column?

Increased energy levels mean valence electrons are further from the nucleus, resulting in a larger atomic radius.

Why does electronegativity (EN) increase across a row?

Increasing protons lead to stronger positive charge that attracts electrons more strongly, making it harder for other atoms to pull them away.

Why does EN decrease going down a column?

Increasing AR means valence electrons are further from the nucleus and experience more shielding, resulting in weaker pull on shared electrons.

Why does electron affinity increase going across a row?

As atomic radius increases, the added electron is further from the nucleus and experiences weaker attraction, needing less energy to be gained.

Difference between an atom and an ion

An atom is neutral while an ion is charged.

Compare ionization of metal atoms to that of metal ions

Metal atoms lose electrons to become ions; the valence shell size is larger as an atom.

Compare ionization of nonmetal atoms to nonmetal ions

The increase in the number of electrons causes greater electron repulsion in the valence shell, increasing the size of the ion.