valence electrons are the electrons in the outside or valence electron shell of an atom
The electrons that determine valence – how an atom reacts chemically – are those with the highest energy
the number of valence electrons that an atom may have depends on the electron configuration
As you move from left to right across a main group period of the periodic table, atomic radii decrease
The number of valence electrons increases from top to bottom within each group
An s orbital is a spherical region within the electron cloud that can contain a maximum of two electrons with opposite spins
A p orbital has two orbital lobes, and an orbital node at the nucleus.
The d orbital is a clover shape because the electron is pushed out four times during the rotation when an opposite spin proton aligns gluons with three spin-aligned protons.
At the fourth and higher levels, there are seven f orbitals in addition to the 4s, 4p, and 4d orbitals.
Each H atom (group 1) has 1 valence electron, and the O atom (group 16) has 6 valence electrons, for a total of 8 valence electrons.
Elements whose atoms can have the same number of valence electrons are grouped together in the periodic table of the elements since the number of valence electrons in an atom governs its bonding behavior.