Respuesta :
The following sets of elements have the same number of valence electrons : B, Al, Ga because they are in the same group
Further explanation
In an atom, there are levels of energy in the shell and subshell
This energy level is expressed in the form of electron configurations.
Valence electrons are electrons used in a chemical bond , and in an atom's outermost energy level
The periodic system of elements is an arrangement of elements classified based on similar properties and their atomic number order.
The periodic system is divided into groups (vertical order) and periods (horizontal order)
Tn the periodic system
In one group will have the same number of valence electrons (except the He element in group VIIIA and the elements in the transition group), while in one period will have the same number of shells
B, Al, Ga because they are in the same group
Electron configuration :
₅B = 2 3
₁₃Al = 2 8 3
₃₁Ga = 2 8 18 3
₄₉In = 2 8 18 18 3
₈₁Tl = 2 8 18 32 18 8 3
The configuration above shows that the valence electrons from group 3 are the same, i.e. 3 electrons
The sets of elements have the same number of valence electrons is Boron, aluminum and galium.
What are valence electrons?
Those electrons which are present on the outer most shell of an atom will known as valence electrons.
In the periodic table elements are arranged in the increasing order of their atomic number and arranged in different periods and groups. Elements of the same group will have the same number of valence electrons. Boron, aluminum and galium are belongs from the same group i.e. 13th group of the p-block elements and will have same valence electrons.
Hence option (2) is correct.
To know more about valence electrons, visit the below link:
https://brainly.com/question/13552988
