Francium has 87 electrons; 87-76=11.
The chemical element with 11 electrons is sodium (Na).
Francium and fluorine form an ionic bond. Francium, being a highly reactive metal, will lose its 1 valence electron to fluorine, a highly electronegative non-metal, which will gain the electron to achieve a full valence shell. This transfer of electrons results in the formation of an ionic bond between the two atoms.
Its kind of like how a battery works. The salt from the saliva in your mouth conducts electrons from the metal of your braces to pass through the other metal to your tongue.
The corrosion of metals involves a redox reaction. In an oxidation-reduction or redox reaction, metals lose electrons to oxygen to form a ionic compound from the metal ions and an ion of the oxide.
Non-metals gain electrons. Hence, they can easily form anions.
Metallic bonds are the electrostatic bonds between metal atoms. The positively charged metal ions bond with the valence electrons of the bonding metal.
The reaction between a metal and oxygen to form a metal oxide is typically an oxidation-reduction (redox) reaction. In this process, the metal undergoes oxidation as it loses electrons, while oxygen is reduced as it gains electrons. This type of reaction is exothermic, often releasing heat and light, and is fundamental in various applications, including combustion and rusting.
Francium occurs in nature (in very, very small quantities) as a decay product of other radioactive materials. "Why" is kind of a pointless question: it just is. it is extremely ephemeral. The longest half-life of any isotope of Francium is 22 minutes.
Non metals generally form anions. They gain electrons during ionic bonding.
Well it kind of depends on what you mean by reactive. The most unstable is Potassium. If you drop it in water it will go up in flames. The one that will produce the greatest energy from burning is Aluminum however Oxygen makes a barrier oxide on the metal that is very very unreactive so you can eat with an aluminum fork but once you get it burning it will burn through most anything.
A metallic bond is formed by delocalized electrons, which are free to move throughout the structure of a metal. These electrons are not associated with any one particular atom, giving metals their characteristic properties such as conductivity and malleability.
The reaction between a metal and a non-metal typically forms an ionic bond, where the metal atom loses electrons to become positively charged (cation) and the non-metal atom gains those electrons to become negatively charged (anion). The oppositely charged ions are then attracted to each other, creating the ionic bond.
A substance that contains a sea of electrons is typically a metal. In metals, the outer electrons are free to move throughout the material, creating a "sea" of delocalized electrons that allows for good electrical conductivity.