When electrons are filling energy levels, the lowest energy sublevels are occupied first. This is Hund's rule.
Hund's rules state that:
Every orbital in a sublevel has to be singularly occupied before any other orbital is able to be doubly occupied.
All of the electrons in single occupied orbitals have to have the same spin to maximize the total spin.
Explanation:
Na represents the neutral element; Sodium. Because of it's atomic number of 11, It has 11 electrons.
Na+ on the other hand represents a cation. The sodium ion has lost an electron, hence the total number of electrons it has = 10.
The K and L shells each have maximum number of electrons they can accommodate. This is given by the formular; 2n^2
K shell = 2 (1)^2 = 2 electrons
L shell = 2 (2)^2 = 8 electrons
Seeing as Na+ has 10 electrons, It completely filled the K and L shells ( 2 + 8 = 10 )
No it is an amino acid present in the synthesis of certain proteins. Elements are pure substances so an acid (which is a compound of different elements) would not be considered an element.
The exosphere is the uppermost layer of Earth's atmosphere
they both describe atoms as being made up of positive and negative matter