A closed container is any container sealed by means of a lid or other device that neither liquid nor vapor will escape from at ordinary temperatures.
“Ordinary” is the answer, hope this helps! :)
The primary greenhouse gases<span> in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Without </span>greenhouse gases<span>, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).</span>
Answer:
<em>The parent isotope in the given elements is Radium 226.
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Explanation:
The two elements given in the question are radioactive elements radon and Helium which are formed after an Alpha decay happens in the radium 226 to form Radon 222.
Radon has many isotopes out of which here radon 222 is formed which is a noble gas that is odourless colourless but Radioactive. Again in this reaction helium is formed which is again a noble gas and very light in weight.
In the column have the same electrons on the outer shell. Which the outer shell electrons are call valence electrons.
