CREATE TABLE table_name_10 (sodium VARCHAR(255), lithium VARCHAR(255), rubidium VARCHAR(255))
what is the properties of sodium when lithium is h a l o g e n s and rubidium is nacl (2.1)?
    
SQL: SELECT sodium FROM table_name_10 WHERE lithium = "h a l o g e n s" AND rubidium = "nacl (2.1)"