Answer:
it readily gains another electron. the outer electron shell is closer to the nucleus, than iodine for example, which makes it less shielded (greater attraction for another electron = violent reaction to get it)
Explanation:
There would be eighteen bonding electrons
2x 6.022x10^23= 1.204x10^24
27*9=243 if one mole is equal to 27 grams times that by 9