Which diagram shows the correct way to represent an ionic compound of magnesium oxide?

Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to incandescence for long periods of time. natural thorium is almost 100% ^{232}\text{th} ​232 ​​ th, with a half-life of 1.405\times 10^{10}~\text{y}1.405×10 ​10 ​​ y. if an average lantern mantle contains 300 mg of thorium, what is its activity?

Ais a mountain created from eruptions of lava, ash, rocks, and hot gases.

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