What is the atomic number of Francium?

Francium has atomic number 87, which means a neutral atom has 87 protons and 87 electrons.

What is the chemical symbol for Francium?

The chemical symbol for Francium is Fr.

What category is Francium in?

Francium is classified as a alkali metal and sits in period 7 of the periodic table.

Element 87

Francium (Fr)

Francium is a chemical element with symbol Fr and atomic number 87. It was discovered by Marguerite Perey in France in 1939. It is the second-most electropositive element, behind only cesium, and is the second rarest naturally occurring element.

Atomic Number

Atomic Mass

223 u

Period

Group

Group 1: alkali metals and hydrogen

Phase

solid

Density

1.87 g/cm3

Electron Shells

2, 8, 18, 32, 18, 8, 1

Atomic Structure

Protons: 87. Electrons: 87. Neutrons: Varies by isotope.

Electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s¹

Why Francium Matters

Francium helps connect atomic number 87, alkali metal behavior, period 7 trends, and electron shell structure. Its solid phase, atomic mass of 223 u, and electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s¹ make it useful for comparing bonding patterns across the periodic table.

Discovery and Occurrence

Francium was discovered 1939 by Marguerite Perey. Francium is a chemical element with symbol Fr and atomic number 87. It was discovered by Marguerite Perey in France in 1939. It is the second-most electropositive element, behind only cesium, and is the second rarest naturally occurring element.

Safety and Handling Context

Francium has radioactive isotopes or is commonly discussed with radioactive materials. Use this page as an educational reference; real samples require qualified supervision and controlled handling.

Related Elements

Frequently Asked Questions

What is the atomic number of Francium?: Francium has atomic number 87, which means a neutral atom has 87 protons and 87 electrons.
What is the chemical symbol for Francium?: The chemical symbol for Francium is Fr.
What category is Francium in?: Francium is classified as a alkali metal and sits in period 7 of the periodic table.

Explore Francium in 3D

Use the interactive table above to rotate atomic models, compare periodic trends, and move from Francium to neighboring elements without losing your place.