Block (periodic table) the s-block, with its outer (and only) electrons in the 1s atomic orbital, although its chemical properties are more similar to the p-block noble gases due to its full shell. In addition to the blocks listed in this table, there is a hypothetical g-block which is not pictured here. The g-block elements can be seen in the expanded extended periodic table. Lanthanum and actinium are placed under scandium and yttrium to reflect their status as d-block elements, as they have no electrons in the 4f and 5f orbitals, respectively, while lutetium and lawrencium do. The s-block is on the left
Symbol table stored with or linked to the symbol table. Most compilers print some or all of this information in symbol table and cross-reference listings at the end of translation. Numerous data structures are available for implementing tables. Trees, linear lists and self-organizing lists can all be used to implement a symbol table. The symbol table is accessed by most phases of a compiler, beginning with lexical analysis, and continuing through optimization. A compiler may use one large symbol table for all symbols or use separated, hierarchical symbol tables for different scopes. For example, in a scoped language such as Algol or