Identify the number of atoms of silver that are in 0.2124 moles of silver

1.28 x 10²³ silver atoms.

Explanation:

Using cross multiplication:

1.0 mole of silver → 6.022 x 10²³ silver atoms.

0.2124 mole of silver → ??? silver atoms.

∴ The no. of atoms of silver that are in 0.2124 moles of silver = (0.2124 mole)(6.022 x 10²³) / (1.0 mole) = 1.28 x 10²³ silver atoms.

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.