Exploring Periodic Table Trends

Elements are organized by atomic number.

The sodium ion (Na⁺) has a smaller radius than the neutral sodium atom (Na).

Elements in a group have similar chemical properties.

Its 1 valence electron is very far from the nucleus, so little energy is needed to remove it.

Mg²⁺, Sr²⁺, Sr.

The atomic number is the number of protons in the nucleus of an atom.

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

Ionization energy generally increases across a period from left to right.

Atomic radius generally increases down a group.

Valence electrons are the electrons in the outermost shell of an atom.