The atmosphere of earth is made of five main layers.
1) Troposphere : This is the lowest part of the atmosphere. Most of the air that makes up the atmosphere is present in this layer.
2) Stratosphere : This layer is present above troposphere and extends up to 50 km. It contains ozone layer which prevents the harmful ultraviolet rays from the sun from entering the lower troposphere
3) Mesosphere : The layer above stratosphere is known as mesosphere.
4) Thermosphere : The region lies above mesosphere.
5) Exosphere : The is the outermost region of the atmosphere.
From the above discussion we can see that the layer that lies between exosphere and mesosphere is Thermosphere
The proton has two adjacent protons, so it splits into three peaks, a triplet. The proton has three adjacent protons, so it splits into four peaks, a quartet.
A) a column
example: earth alkaline metals
<h3>Answer:</h3>
18.75 grams
<h3>Explanation:</h3>
- Half-life refers to the time taken by a radioactive material to decay by half of the original mass.
- In this case, the half-life of element X is 10 years, which means it takes 10 years for a given mass of the element to decay by half of its original mass.
- To calculate the amount that remained after decay we use;
Remaining mass = Original mass × (1/2)^n, where n is the number of half-lives
Number of half-lives = Time for the decay ÷ Half-life
= 40 years ÷ 10 years
= 4
Therefore;
Remaining mass = 300 g × (1/2)⁴
= 300 g × 1/16
= 18.75 g
Hence, a mass of 300 g of an element X decays to 18.75 g after 40 years.
