Periodic table period
Period 3
Period 3 is a horizontal row of the periodic table with 8 elements, from Sodium (atomic number 11) to Argon (atomic number 18). Every element in the row has 3 occupied electron shells. Period 3 fills the 3s and 3p subshells. It runs from the soft metal sodium through silicon, the backbone of electronics, to the noble gas argon.
At a glance
- Elements
- 8
- Atomic numbers
- 11 to 18
- Blocks
- s-block, p-block
- Period
- 3
- Phase at STP
- solid (6), gas (2)
Shared properties
- Each member has 3 occupied electron shells
- Atomic radius generally decreases from left to right across the period
- Ionization energy and electronegativity generally increase across the period
- Character shifts from metallic on the left to nonmetallic on the right