Question

1.Which diatomic molecule below would be useful in saying good-bye?

O2
N2
I2
Ta2
Li2

2.Which element is best for use in flash bulbs?
Mn
Mg
Cs
Ca
Sr

Magnesium is often used in old time flash bulbs, if they still exist.
]

I have no idea on the first.

TaTa?

O2 for the first one!