Suppose that a newly discovered element called centium has 3 isotopes that occure in nature. These are centium -200, centium -203, and centium -209. Assume that these isotopes occur in equal amounts in nature. What will be the average atomic mass of this element

I'm super confused

The answer to your question is 203.8 g

Explanation:

Data

Average atomic mass = ?

Centium-200

Centium-203

Centium-209

Equal amounts

Process

1.- Determine the abundance of each isotope.

If they are in equal amounts in nature, just divide 100 by 3

             100/3 = 33.33 % or 0.333

2.- Determine the Average atomic mass

Average atomic mass = Atomic mass 1 x abundance + Atomic mass 2 x

                                        abundance + Atomic mass 3 x abundance

- Substitution

Average atomic mass = 200 x 0.333 + 203 x 0.333 + 209 x 0.333

- Simplification

Average atomic mass = 66.6 + 67.6 + 69.6

Result

Average atomic mass = 203.8 g

sodium (na), for example, has one electron in its valence shell. this is an unstable state because that valence shell needs eight electrons to be full. in order to fill its valence shell, find a way to add seven electrons to its valence shell