My predicted boiling point for Francium is 27°c
Figures obtained from:
My predicted boiling point for Francium is 667°c
Alkali metals often react violently, especially with substances such as water, halogens or Group 6 elements. This is due to their lone electron occupying the outer shell which is weakly attracted to the nucleus; therefore it is easily lost to other compounds with a high a tendency to attract/accept electrons such as hydrogen. As you go down the group the attraction between the only electron and the nucleus weakens, the reactivity increases and the reaction gets more violent.
Adding alkali metals to water will cause an exothermic reaction such as explosions, and can be very dangerous. Some alkali metals can react violently with just moisture in the air. Most of the alkali metals float on the top of the surface of the water, for example sodium fizzes on the surface of the water [3]. The size of the alkali metal determines the size of the reaction. During the reaction hydrogen gas is given off and alkali metal hydroxide is formed as a product.
Word equation for the reaction of alkali metal with water is:
Alkali Metal + Water » Metallic Hydroxide + Hydrogen
The symbolic equation for the reaction of sodium with water is:
2Na + 2H2O = 2NaOH + H2
The symbolic equation for the reaction of Potassium with water is:
2K + 2H2O = 2KOH+ H2
As we know that, as we move down the group reactivity increases, so I predict that francium would be more reactive and more violent than the other alkali metals. There would be a percussive reaction with a loud bang and instant vaporization of water, producing a lot of steam, plus burning hydrogen, since hydrogen is also a product. [4]
You would also see whatever the characteristic colour of burning Francium would be.
In alkali metals, as you go down the group the melting point decreases while the atomic radius increases. This is because the increase in atomic radius means that there is more space between the nucleus and the electron in the outer shell, the more space means that there is less force of attraction between the nucleus and the electrons further away from the nucleus. So less energy is required to break the forces of attraction within the atom.[5] For example, has an of 2,1 so it only has two shells so there are forces of attraction between the shells which means more energy is required to break these forces. Whereas, has an electronic configuration of 2,8,8,1 thus it has 4 shells, therefore there is less force of attraction between the shells which means less energy is required to break these forces of attraction between the shells.
That is the reason why there is pattern in melting points (The increase in atomic number and the decrease in the force of attraction within the atom). [5]
In the Bohr Model the neutrons and protons occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun but with electrostatic forces providing attraction, rather than gravity. [6] The electrons, which orbit around the nucleus, occupy several energy levels, where the closest electron has the strongest force of attraction to the nucleus. When these electrons get energy, they move up to another energy level. This new energy level is still a circle. If this electron get even more energy, it moves up to another energy level, but when this electron loses energy, it moves down to a smaller energy level. So the Bohr model looks like a point (that represents the nucleus) with circles (energy shells/level) around it, each circle that is surrounded by another.
The Bohr can be used to explain the reactivity of alkali metals because the higher energy that the outer is situated in, the less forces are upon it from (because the outer As there is only one is , in alkali metals, it is easily removed to become stable. Their reactivity increases as you go down the group as the electron you lose is further from the positive nucleus attracting it, which is also shielded by the electrons in between.[7] This makes it easier for the outer electron to be lost.
REFRENCE
