How many elements does barium have to give up to achieve a noble-gas electron configuration?

2 electrons

Explanation:

Barium is present in group two. It is alkaline earth metal.

It has two valance electrons. In order to achieve noble gas configuration it loses its two valance and get complete octet.

Electronic configuration:

Ba₅₆ = [Xe] 6s²

When it loses two electron it get configuration of xenon.

Chemical properties of barium:

It form salt with halogens.e.g

Ba    +   Br₂    →     BaBr₂

IT react with oxygen and form oxide.

2Ba   +   O₂   →    2BaO

this oxide form hydroxide when react with water,

BaO  + H₂O   →  Ba(OH)₂

With nitrogen it produced nitride,

3Ba + N₂     →  Ba₃N₂

With acid like HCl,

Ba + 2HCl  →  BaCl₂ + H₂

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

you need to have a picture of the atom that way we can answer it