Periods & Groups
Horizontal rows on the periodic table are called this.
Periods
Atomic radius increases in this direction.
Down a group
Alkali metals react violently with this substance.
Water
Electrons occupy these regions around the nucleus.
Orbitals
This element is needed for respiration.
Oxygen
Vertical columns are called this.
Groups
Atomic radius decreases across a period in this direction.
Left to right
Halogens are highly reactive because they need this.
One electron
The outermost electrons are called this.
Valence electrons
This element is the main component of steel.
Iron
Elements in the same group share this.
Similar properties
This measures attraction for electrons in a bond.
Electronegativity
Noble gases are unreactive due to this.
Full outer shell
This rule states no two electrons have identical quantum numbers.
Pauli exclusion principle
This element has symbol Al.
Aluminum
This group contains the most reactive metals.
Group 1 (alkali metals)
This measures energy required to remove an electron.
Ionization energy
This alkali metal reacts explosively with water and is often stored in oil.
Sodium
This rule states electrons fill lowest energy first.
Aufbau principle
This element is used in neon lights.
Neon
This group contains gases with full valence shells.
Group 18 (noble gases)
Electronegativity is highest in this element.
Fluorine
This halogen is a liquid at room temperature.
Bromine
This rule states electrons fill singly before pairing.
Hund’s rule
This element is the lightest gas.
Hydrogen