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

The element with atomic number 11 is Sodium, represented by the chemical symbol Na. According to its electronic configuration, sodium has 11 electrons distributed as 2 in the K shell, 8 in the L shell, and 1 in the M shell (2, 8, 1) [1]. Valency is defined as the combining capacity of an element, which depends on the number of valence electrons in its outermost shell [3]. Since sodium has only one electron in its outermost shell, it readily loses this electron to achieve a stable octet configuration, resulting in a valency of 1 [1]. In contrast, Lithium has an atomic number of 3, Boron has 5, and Magnesium has 12. Therefore, the correct name, symbol, and valency for atomic number 11 are Sodium, Na, and 1 respectively.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.3 HOW DO METALS AND NON-METALS REA ALS REACT? > p. 46
2. [3] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.3 HOW DO METALS AND NON-METALS REA ALS REACT? > p. 47