If an atom of sodium combines with (captures) an alpha particle that has 2 protons and 2 neutrons, its new mass number will be
a)
13 amu
b)
15 amu
c)
25 amu
d)
27 amu

27 amu

Explanation:

The alpha particles is Helium nuclei.

Atomic mass is the sum of the neutrons and protons.

Helium have two protons and two neutrons thus its atomic mass is 4 amu.

₂He⁴

Sodium atom have 12 neutrons and 11 protons. Thus its mass number will be

23 amu.

When it combine with alpha particle it mass will be 27 amu.

23 amu + 4 amu = 27 amu.

Thus new sodium atom have 14 neutrons and 13 protons.

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.