diff --git a/1A_elements.txt b/1A_elements.txt
index 7ecd27a..b556724 100644
--- a/1A_elements.txt
+++ b/1A_elements.txt
@@ -1,2 +1,3 @@
 H(1)
-Li(3)
\ No newline at end of file
+Li(3)
+Na(11)