diff --git a/1A_elements.txt b/1A_elements.txt
index 6448618..d031725 100644
--- a/1A_elements.txt
+++ b/1A_elements.txt
@@ -2,4 +2,4 @@ H(1)
 Li(4)
 Na(11)
 K(19)
-
+Rb(37)