It depends what element for example, lithium would need to gain 7 electrons or lose 1 so that the outer-most shell is full. However, elements like neon (which is a noble gas) don't need to gain or lose any electrons since the outer shell is already filled. It depends on it's place in the Periodic Table of the elements.
Its atomic number is 7, and so it needs a further 3 electrons to fill its outer shell.
An atom of nitrogen has 5 electrons in its outer shell. This makes nitrogen a nonmetal and means it requires 3 more electrons to fill its outer shell and become stable.
As Nitrogen (N) have atomic number 7, and electronic configuration is 2,5. therefore N required 3 elecrons to complete their outermost shell or orbital.
Nitrogen has two energy levels. The first energy level contains two electrons. The second energy level contains five electrons. Number of Protons/Electrons: 7 Number of Neutrons: 7
The halogen family tends to gain one electron to fill their outer shell.
Carbon has four valence electrons, so it will need four more electrons to fill its outer shell.
4 to fill the 2p shell
There is a total of 8 electrons that are needed to fill outer shell of most atoms. An atom is the smallest unit of matter.
8
Carbon needs 4 electrons to fill up its outer shell. It has 4 valence electrons and can achieve a full octet by gaining 4 more electrons.
Nitrogen needs 3 more electrons to fill its outer shell. It has 5 electrons in its outer shell, and it typically needs a total of 8 electrons to achieve a full outer shell (octet rule).
8
Sulfur has 6 electrons in its outer shell. Therefore, it needs 2 more electrons to fill its outer shell.
Carbon has four valence electrons, so it will need four more electrons to fill its outer shell.
Beryllium will lose 2 electrons to satisfy the octet rule (to fill its outer shell).
Its atomic number is 7, and so it needs a further 3 electrons to fill its outer shell.
Sodium has ONE valence electron in its outer shell that is to be donated to any kind of oxidant. By then the outer (3rd) shell (of the Na+ ion) is EMPTY, so the 2nd shell has become the outmost, containing 8 electrons (Ne-configuration). No electrons at all are taken up by sodium.