Periodic table group
Group 1
Group 1 is a vertical column of the periodic table containing Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium, Francium. Elements in the same group have the same number of valence electrons, which is why they show related chemical behavior. Hydrogen heads the group because of its single s electron, but chemically it is a reactive nonmetal; the metals beneath it are the alkali metals, which lose that electron to form +1 ions and react vigorously with water.
At a glance
- Elements
- 7
- Atomic numbers
- 1 to 87
- Block
- s-block
- Periods
- 1, 2, 3, 4, 5, 6, 7
- Phase at STP
- solid (5), gas (1)
Shared properties
- Same valence electron count, so members react in related ways
- Atomic radius increases down the group as electron shells are added
- First ionization energy generally decreases down the group
The 7 elements
Frequently asked questions
What elements are in group 1?
Group 1 contains 7 elements: Hydrogen, Lithium, Sodium, Potassium, Rubidium, Cesium, Francium.
What properties do group 1 elements share?
Elements in group 1 have the same number of valence electrons, so they react in related ways. Atomic radius increases down the group as electron shells are added, and first ionization energy generally decreases down the group. Hydrogen heads the group because of its single s electron, but chemically it is a reactive nonmetal; the metals beneath it are the alkali metals, which lose that electron to form +1 ions and react vigorously with water.
Why are they called the alkali metals?
The metals of group 1, from lithium down to francium, are the alkali metals: they react vigorously with water, releasing hydrogen gas and forming alkaline hydroxides. Hydrogen also sits in group 1 because of its single s electron, but chemically it is a reactive nonmetal, not an alkali metal.