The word "valance" is used to describe electrons in the outer-most energy level of an atom.
Oxygen has six valance electrons.
8 electrons
You mean valence electron? 2 If your talking about Bohr Diagrams then it depends on the metal
There are 8 electrons in the outer level of all the noble gases except helium. This full outer level gives them stability and makes them less reactive. Helium, as a noble gas, has only 2 electrons in its outer level.
Potassium has 1 electron in its outer energy level. When it forms a bond, it typically donates this electron to another element, leaving it with a full outer energy level.
What causes these to be so reactive is the amount of electrons in the outer most level. Each level after the first (which has 2 if full) if filled will have 8 electrons. Halogens have less than that causing it to be reactive to other elements. (i don't know how many electrons it has in the outer level) The reason why it is reactive is (depending on how many electrons it has in the outer leve) because it is either trying to gain or lose those extra electrons. What causes these to be so reactive is the amount of electrons in the outer most level. Each level after the first (which has 2 if full) if filled will have 8 electrons. Halogens have less than that causing it to be reactive to other elements. (i don't know how many electrons it has in the outer level) The reason why it is reactive is (depending on how many electrons it has in the outer leve) because it is either trying to gain or lose those extra electrons.
Nitrogen has 5 electrons in its outer shell, and Bromine has 7 electrons in its outer shell.
Uranium has 2 electrons on its outer energy level.
Boron has 3 electrons in it's outer level.
Vanadium has 5 electrons in its outer energy level.
7Fluorine has 7 electrons in the outer level.
10 electrons
Iodine has 7 electrons in its outer energy level.
Mercury has 2 electrons in its outer level, which is the 6th and final energy level for mercury.
There are 8 electrons in the outer energy level of xenon. Xenon belongs to the noble gas group on the periodic table, which have a full outer energy level with 8 electrons.
Magnesium has 2 electrons on its outer energy level.
There are three electrons in boron's outer energy level.
Two electrons