Which of the following compares longwall mining to solution mining? Longwall mining involves a series of explosion while solution mining is used to shear coal from mine walls.
Longwall mining involves hot water injected into the ore to dissolve it while solution mining involves a series of explosion.
Longwall mining involves hot water injected into the ore to dissolve it while solution mining is used to shear coal from mine walls.
Longwall mining is used to shear coal from mine walls while solution mining involves hot water injected into the ore to dissolve it.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

the objects have the same charge.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.