It isn't. Electrons surrounding atoms are arranged in energy levels. Each energy level can carry a certain number of electrons. The innermost energy level can hold up to two electrons, the second and third levels have up to eight each, the fourth has a capacity of 16... If ever an atom (such as a noble gas) or an ion has a full outer shell, it is considered stable unreactive and, for want of a better word, "happy".
The maximum number of electrons in the second energy level of an atom is 8.
the largest number of electrons an atom of helium can have is 2, because it is in the first period, which means it can only have one energy level, which has a maximum capacity of two electrons
an atom's outer energy level doesn't have the maximum number of electrons.
The most valence electrons an atom can contain is eight.
2 electrons
Every oxygen atom has eight electrons.
Every oxygen atom has eight electrons.
The number of protons in an atom is equal to the number of electrons in the atom. Therefore, the total number of electrons in an atom can be found by determining the atom's proton number. For example, the proton number of oxygen is eight. Thus, an oxygen atom has eight protons and eight electrons.
8
8
electrons
8