Answer:
The atomic number of Selenium is 34. This means that Selenium possesses 34 electrons.
The atomic number of Aluminium is 13. This means that Aluminium has 13 electrons.
Hence, there is a difference of 21 between the number of electrons in an atom of selenium and the number of electrons in an atom of aluminium.
Selenium has 6 electrons in it's outer most shell whereas aluminium has 3 electrons in its outer most shell. As a result, aluminium will have a greater tendency to lose one of its outer most electrons to become stable.
In group 1, elements get more reactive going down the group. Sodium is more reactive than lithium since when going down, each element gains an extra valence electron, and the outer shell electrons get further and further away from the nucleus while also becoming more in number. Due to this, the element becomes unstable and more reactive.
Dmitri Mendeleev was the creator and therefore organizer of the periodic table.
A) Low ionization energy correlates to elements with fewer valence electrons.
Ionization energy is the energy required to separate valence electrons from their atom. The more valence electrons there are, the higher the ionization energy.
Hope this helps!
