How every many it takes to achieve a stable valence shell. Most of the time this is 8.
Most atoms seek to have a full outer electron shell, consisting of 8 electrons (or 2 electrons in the case of hydrogen and helium). This is known as the octet rule. However, there are exceptions to this rule for certain elements.
An atom of helium has 2 electrons.
A stable sodium atom has 11 electrons.
13
Copper atom has 29 electrons.Uranium atom has 92 electrons.
A phosphorus atom has 15 electrons.
An atom of nitrogen has 7 electrons.
An atom of helium has 2 electrons.
A Mercury atom has 80 electrons.
The number of electrons depends on what type of atom it is.
A germanium atom has 32 electrons.
The neutral atom of potassium has 19 electrons.
An atom of selenium has 34 electrons.
A copper atom has 29 electrons.
There are 17 electrons i a neutral atom of chlorine.
The neutral atom of phosphorus has 15 electrons in the atom.
An atom of Argon typically has 18 electrons.
A sodium atom has 11 electrons.