Table: atomic_radii
Columns: number
symbol
name
empirical
calculated
van_der_waals
covalent_single_bond
covalent_triple_bond

Question: What is the symbol of the element with an empirical t of 190 and a calculated value of 135?
SQL: SELECT "symbol" FROM atomic_radii WHERE "empirical" = '190' AND "calculated" = '135'

Question: What is the name of the element with a calculated value of 56?
SQL: SELECT "name" FROM atomic_radii WHERE "calculated" = '56'

Question: What is the covalent (single bond) value of sodium?
SQL: SELECT "covalent_single_bond" FROM atomic_radii WHERE "name" = 'sodium'