If atomic number of an element is 11, the correct name, symbol and valency are:

The element with atomic number 11 is Sodium, with symbol Na (from Latin 'Natrium') and valency 1. Sodium has the electronic configuration 2, 8, 1, with one electron in its outermost shell. To attain a stable noble gas configuration, sodium loses this one electron, giving it a valency of 1 and forming the Na+ ion. Lithium has atomic number 3, Boron has atomic number 5, and Magnesium has atomic number 12. Sodium is an alkali metal belonging to Group 1 of the periodic table.