Strontium is a chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.
Three reasons Strontium stands out
1
Used in fireworks for red color.
2
Its radioactive isotope is a significant nuclear fallout product that can substitute for calcium in human bones.
3
It was used in cathode-ray televisions to absorb X-rays emitted by the screen and protect viewers.
The crimson signature in a flame
Strontium salts color fireworks and emergency flares a saturated red. Chemically it resembles calcium closely enough that the body may place it in bone; that makes radioactive strontium-90 especially hazardous after nuclear fallout. Stable strontium isotopes, meanwhile, can trace where ancient people and animals lived.
Recognizing Strontium in Elementle
If Strontium is the mystery element, guesses below atomic number 38 point up and guesses above it point down. Its symbol is Sr: a green letter matches the same position in that symbol, while a yellow letter belongs in another position.
The family clue turns green for alkaline earth metal guesses. Compare Calcium (Ca), number 20 and Barium (Ba), number 56: they share the family clue, but their atomic numbers and symbols help you tell them apart.
Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.
The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.