The octet rule does not apply to transition and inner transition metals and to the first for or five elements in the periodic table.
A chlorine ion with a stable arrangement of eight valence electrons is called a chloride ion (Cl-). It achieves this stable arrangement by gaining one electron from another atom to fill its outermost electron shell.
Cl-
An atom with five valence electrons can achieve a full set of eight valence electrons by either gaining three electrons (to reach a stable octet) or losing three electrons to have a stable arrangement. This would result in the atom forming an ionic bond, such as in the case of boron transferring three electrons to become the boride ion.
Boron tends to form molecules in which it is surrounded by only six valence electrons. Boron only has three valence electrons, and fluorine already has seven of the eight electrons it needs to fulfill its octet to be stable. Hope it helps!
The element with a stable 2 valence electrons is helium. Helium has a full outer electron shell with 2 electrons, making it very stable and unreactive.
stable electronic configuration
A chlorine ion with a stable arrangement of eight valence electrons is called a chloride ion (Cl-). It achieves this stable arrangement by gaining one electron from another atom to fill its outermost electron shell.
Cl-
8 valence electrons
An atom with five valence electrons can achieve a full set of eight valence electrons by either gaining three electrons (to reach a stable octet) or losing three electrons to have a stable arrangement. This would result in the atom forming an ionic bond, such as in the case of boron transferring three electrons to become the boride ion.
The most stable outer orbital arrangement of electrons is a full valence shell. This occurs when an atom has all its outermost energy level electrons filled. Elements strive to achieve the electron configuration of noble gases, which have a full outer shell of electrons and are considered to be very stable.
Helium is stable with 2 valence electrons. It has a full outer electron shell, making it chemically inert and stable.
An oxygen atom has 6 electrons in its outer shell, therefore it needs two more to have a stable configuration of 8 electrons. That's why the valence is two.
Boron tends to form molecules in which it is surrounded by only six valence electrons. Boron only has three valence electrons, and fluorine already has seven of the eight electrons it needs to fulfill its octet to be stable. Hope it helps!
The element with a stable 2 valence electrons is helium. Helium has a full outer electron shell with 2 electrons, making it very stable and unreactive.
Neutral Carbon atoms contain 6 electrons and 6 protons 2 electrons are found in the 1st electron ring and 4 in the outer ring to reach a stable electron (8 in the outershell) arrangement carbon requires 4 covalent bonds to be formed
Noble gases have a full outer electron shell, making them stable and chemically inert. This arrangement gives them little tendency to gain, lose, or share electrons with other atoms, making them nonreactive under normal conditions.